Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus yunnanensis.In the present study,three PAL genes we...Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus yunnanensis.In the present study,three PAL genes were cloned and identified from P.yunnanensis seedlings for thefirst time,namely,PyPAL-1,PyPAL-2,and PyPAL-3.Our results indicated that the open-reading frames of PyPAL genes were 2184,2157,and 2385 bp.Phylogenetic tree analysis revealed that PyPALs have high homology with other known PAL genes in other plants.In vitro enzymatic analysis showed that all three PyPAL recombinant proteins could catalyze the deamination of L-phenylalanine to form trans-cinnamic acid,but only PAL1 and PAL2 can catalyze the conversion of L-tyrosine toρ-coumaric acid.Three PyPAL genes were expressed in different tissues in 1-year-old P.yunnanensis,and such genes had different expression patterns.This study lays a foundation for further understanding of the biosynthesis of secondary metabolites in P.yunnanensis.展开更多
Rhizopus rot of peach fruits could be significantly suppressed by Pichia membranefaciens.Polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonium-lyase (PAL) activities inducedby inoculation with P. membr...Rhizopus rot of peach fruits could be significantly suppressed by Pichia membranefaciens.Polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonium-lyase (PAL) activities inducedby inoculation with P. membranefaciens or R. stolonifer were studied in postharvest peach fruits. The activ-ities of PPO and PAL in peaches increased significantly after being inoculated with P. membranefaciens + R.stolonifer by 24 h, the activities maintained at a high level throughout the experiment. Under the condition ofinfected with R. stolonifer alone, activity of PPO and PAL could also increased, but the levels were lowerthan those treated with P. membranefaciens+ R. stolonifer. However, fruits inoculaed with P. membrane-faciens+ R. stolonifer or R. stolonifer alone did not stimulated POD activity. The results suggest that theactivation of these defense enzymes is involved in the action of P. membranefaciens against R. stolonifer.展开更多
Objective The aim is to ascertain whether phenylalanine (Phe) can inverse the left heart"remodeling" in patients with essential hypertension. Methods The changes of echocardiographic variables werecompared a...Objective The aim is to ascertain whether phenylalanine (Phe) can inverse the left heart"remodeling" in patients with essential hypertension. Methods The changes of echocardiographic variables werecompared aler 3,6 and 9 months of observation between the Phe intervention group (Phe 1g/d+amiloride complex1 tablet/d, 20 cases) and control group (placebo 1g/d+amiloride complex 1 tablet/d, 20 cases) with eitherinterventricular septum and (or) post- wall thickness≥12mm, and were carried on further to compare incross- over trial. Results (1) Phe improved elfectively the left heart and systolic dyslunction; while theimprovement, also shown in control group due to the concurrent use of diuretic antihypertensive drug-amiloridecomplex, was much less evident than that in Phe group. (2) The disturbed left heart structure and systolic functionwere improved prominently while placebo was crossed over to Phe, and the improvement decreased afer Phe wascrrossed over to placebo. (3) The changes almost attained to its peak level after 6 months and not improved furtherat 9 months. (4) The differences seen between above 2 groops could not be eoplained by their diverse drops of bloodpressure. Conclusion Phe does exert an indopendent inverse effect on cardiac "remodeling", which mightimplicate an important clinical oplication upon the prevention and control of essential hypertension and itscomplications.展开更多
The substrate hippuryl phenylalanine of carboxypeptidase A was selected as model to design new hapten molecule. N-Benzoyl tauryl phenylalanine (I) was synthesized and its structure was characterized by X-ray crystallo...The substrate hippuryl phenylalanine of carboxypeptidase A was selected as model to design new hapten molecule. N-Benzoyl tauryl phenylalanine (I) was synthesized and its structure was characterized by X-ray crystallography method.展开更多
Phenylketonuria(PKU),a disease resulting in the disability to degrade phenylalanine(Phe)is an inborn error with a 1 in 10,000 morbidity rate on average around the world which leads to neurotoxicity.As an potential alt...Phenylketonuria(PKU),a disease resulting in the disability to degrade phenylalanine(Phe)is an inborn error with a 1 in 10,000 morbidity rate on average around the world which leads to neurotoxicity.As an potential alternative to a protein-restricted diet,oral intake of engineered probiotics degrading Phe inside the body is a promising treatment,currently at clinical stage II(Isabella,et al.,2018).However,limited transmembrane transport of Phe is a bottleneck to further improvement of the probiotic’s activity.Here,we achieved simultaneous degradation of Phe both intracellularly and extracellularly by expressing genes encoding the Phe-metabolizing enzyme phenylalanine ammonia lyase(PAL)as an intracellularly free and a cell surface-immobilized enzyme in Escherichia coli Nissle 1917(EcN)which overcomes the transportation problem.The metabolic engineering strategy was also combined with strengthening of Phe transportation,transportation of PAL-catalyzed trans-cinnamic acid and fixation of released ammonia.Administration of our final synthetic strain TYS8500 with PAL both displayed on the cell surface and expressed inside the cell to the Pah^(F263S)PKU mouse model reduced blood Phe concentration by 44.4%compared to the control Ec N,independent of dietary protein intake.TYS8500 shows great potential in future applications for PKU therapy.展开更多
Emerging evidence suggests that amino acids dictate the effector functions of immune cells;however, whether and how phenylalanine(Phe) orchestrates the polarization of macrophages is not understood. Here, we determine...Emerging evidence suggests that amino acids dictate the effector functions of immune cells;however, whether and how phenylalanine(Phe) orchestrates the polarization of macrophages is not understood. Here, we determined that Phe attenuated lipopolysaccharide(LPS) and P. multocida serotype A strain CQ2(PmCQ2) infection-induced inflammation in vivo. Furthermore, we demonstrated that Phe inhibited the production of interleukin(IL)-1β and tumor necrosis factor(TNF)-α in proinflammatory(M1) macrophages. Phe reprogrammed the transcriptomic and metabolic profiles and enhanced oxidative phosphorylation in M1 macrophages, which reduced the activation of caspase-1. Notably, the valine-succinyl-CoA axis played a critical role in Phe-mediated inhibition of IL-1β production in M1 macrophages. Taken together, our findings suggest that manipulating the valine-succinyl-CoA axis provides a potential target for preventing and/or treating macrophage-related diseases.展开更多
How plants produce the important defense hormone salicylic acid(SA)has been studied for almost 50 years.The current understanding is that in land plants,SA is biosynthesized from chorismate through the isochorismate(I...How plants produce the important defense hormone salicylic acid(SA)has been studied for almost 50 years.The current understanding is that in land plants,SA is biosynthesized from chorismate through the isochorismate(IC)pathway and the phenylalanine ammonia-lyase(PAL)pathway(Dempsey et al.,2011).展开更多
With the method of synthesizing the L-phenylalanine by trans-cinnamic acid and ammonia in the presence of phenylalanine ammonialyase (PAL) under high pH and high concentration of cinnamic acid, it is not favorable for...With the method of synthesizing the L-phenylalanine by trans-cinnamic acid and ammonia in the presence of phenylalanine ammonialyase (PAL) under high pH and high concentration of cinnamic acid, it is not favorable for the conversion because of the deactivation of the PAL.For this reason, it is important to find out the suita-展开更多
Background This study aimed to explore the value of applying a new pterin marker (isoxanthopterin) to the traditional urine pterin analysis to reduce the rate of mis-diagnosis of 6-pyruvoyltetrahydropterin synthase de...Background This study aimed to explore the value of applying a new pterin marker (isoxanthopterin) to the traditional urine pterin analysis to reduce the rate of mis-diagnosis of 6-pyruvoyltetrahydropterin synthase deficiency (PTPSD) and improve the accuracy of diagnosis.Methods We compared the urine neopterin (N),biopterin (B),isoxanthopterin (Iso),B% and Iso% levels between patients with phenylalanine hydroxylase deficiency and those with PTPSD,and found the most specific pterin biomarkers by ROC analysis.A positive cut-off value of urine pterins was determined.The effect of combined Iso% + B + B% in reducing PTPSD mis-diagnosis was evaluated,and the different urine pterin levels in PTPSD and false PTPSD (FPTPSD) were compared.The concordance of PTPSD diagnosis by the new pterin scheme and gene mutation analysis was determined.Results (1) Urinary B,B%,Iso and Iso% were significantly lower in PTPSD than those in phenylalanine hydroxylase-deficiency group (P < 0.01);(2) Iso%,B%,and B were the most specific markers;(3) The positive cut-off values of B,B%,Iso% for PTPSD were < 0.17 mmoL/moLCr,< 5.0%,and < 9.5%,respectively;(4) urinary B +B% + Iso% scheme significantly reduced the false-positive rate of PTPSD compared to traditional ones.The Iso% levels in FPTPSD group were higher than the ones in PTPSD group;(5) an accuracy of diagnosis for PTPSD was increased by 9-19% when Iso% was introduced to urinary pterin scheme.Conclusions Iso% is helpful to reduce the rate of misdiagnosis of PTPSD in the diagnosis by urinary pterin analysis for hyperphenylalaninemias and improve the accuracy of diagnosis.This approach is worthy of further development and increased utilization.展开更多
Phenolic compounds, metabolites of the phenylpropanoid pathway, play an important role in the growth and environmental adaptation of many plants. Phenylalanine ammonia-lyase(PAL) is the first key enzyme of the phenylp...Phenolic compounds, metabolites of the phenylpropanoid pathway, play an important role in the growth and environmental adaptation of many plants. Phenylalanine ammonia-lyase(PAL) is the first key enzyme of the phenylpropanoid pathway. The present study was designed to investigate whether there is a multi-gene family in I. Indigotic and, if so, to characterize their properties. We conducted a comprehensive survey on the transcription profiling database by using tBLASTn analysis. Several bioinformatics methods were employed to perform the prediction of composition and physicochemical characters. The expression levels of IiPAL genes in various tissues of I. indigotica with stress treatment were examined by quantitative real-time PCR. Protoplast transient transformation was used to observe the locations of IiPALs. IiPALs were functionally characterized by expression with pET-32a vector in Escherichia colis strain BL21(DE3). Integration of transcripts and metabolite accumulations was used to reveal the relation between IiPALs and target compounds. An new gene(IiPAL2) was identified and both IiPALs had the conserved enzymatic active site Ala-Ser-Gly and were classified as members of dicotyledon. IiPAL1 and IiPAL2 were expressed in roots, stems, leaves, and flowers, with the highest expression levels of IiPAL1 and IiPAL2 being observed in stems and roots, respectively. The two genes responded to the exogenous elicitor in different manners. Subcellular localization experiment showed that both IiPALs were localized in the cytosol. The recombinant proteins were shown to catalyze the conversion of L-Phe to trans-cinnamic acid. Correlation analysis indicated that Ii PAL1 was more close to the biosynthesis of secondary metabolites than IiPAL2. In conclusion, the present study provides a basis for the elucidation of the role of Ii PALs genes in the biosynthesis of phenolic compounds, which will help further metabolic engineering to improve the accumulation of bioactive components in I.indigotica.展开更多
A polymer with suitable physical characters and matched functional groups was synthesized,and used as a supporter to immobilize aminoacylase. The results showed that this supporterhad high immobilizing capacity and hi...A polymer with suitable physical characters and matched functional groups was synthesized,and used as a supporter to immobilize aminoacylase. The results showed that this supporterhad high immobilizing capacity and high selectivity for aminoacylase. Immobilized amino-acylase had high specific activity. In this paper, we determine the physical and chemicalcharacters of aminoacylase for resolution of D,L--phenylalanine, including its optimum tem-perature, pH, ion concentration, activated ion, substrate concentration, thermal stability anddenaturation. The immobilized aminoacylase was used to resolve the D,L-phenylalaninecontinuously. Thc resolved products was separated and purified with ion-exchange resins. L-phenylalanine solution was concentrated by vacuum evaporation and its hydrochloride wasformed. Checking of final product with polarimeter showed high yield and purity.展开更多
It is well known that salinity has badly effect on plant growth all over the world and greatly reduces crop production in the affected regions.Selenium can function as an antioxidant in plants and also in low concentr...It is well known that salinity has badly effect on plant growth all over the world and greatly reduces crop production in the affected regions.Selenium can function as an antioxidant in plants and also in low concentration can promotes plant growth and produce tolerance against stress.This study was conducted in order to determine the effects of selenium(Se)application(0,4,8 and 16 mg L^-1)on phenylalanine ammonia-lyase(PAL)activity,phenol leakage and total phenolic content of garlic under salt stress(0,30,60 and 90 mM NaCl).The highest PAL activity was recorded at 60 and 90 mM NaCl salinity with application of 8mg Se L^-1.Also,when Se was added to the salt-stress garlic,the level of phenol leakage was decreased significantly at two levels of NaCl concentration(by 52%and 40%at 30 mM NaCl with application of 4 and 16 mg Se L^-1,and by 50%at 90 mM NaCl with application of 4mg Se L^-1,respectively)in comparison to the salt-stressed garlic without Se.The results showed that Se can increase the salt tolerance of garlic by protecting the cell membrane against lipid peroxidation.The highest concentration of phenols was recorded at 90 mM NaCl salinity level with application of 4 and 8 mg Se L^-1,that respectively produced 59%and 51%higher phenols than control treatment without Se.So,application of optimal Se level can increase the potential of garlic in a medium with relatively high level of NaCl.展开更多
In the development of new peptide drugs, it is an important way to synthesize the analogs of bioactive peptide. There are different methods to obtain the analogs, including: (ⅰ) changing the backbond structure of a p...In the development of new peptide drugs, it is an important way to synthesize the analogs of bioactive peptide. There are different methods to obtain the analogs, including: (ⅰ) changing the backbond structure of a peptide; (ⅱ) changing the amino acid residues and (ⅲ) introducing D-amino acids into a peptide. In some cases, to get high potent analogs of a peptide, unnatural amino acids are needed.展开更多
Phenylalanine ammonia-lyase(PAL),which catalyzes the conversion from L-phenylalanine to trans-cinnamic acid,is a well-known key enzyme and a connecting step between primary and secondary metabolisms in the phenylpropa...Phenylalanine ammonia-lyase(PAL),which catalyzes the conversion from L-phenylalanine to trans-cinnamic acid,is a well-known key enzyme and a connecting step between primary and secondary metabolisms in the phenylpropanoid biosynthetic pathway of plants and microbes.Schisandra chinensis,a woody vine plant belonging to the family of Magnoliaceae,is a rich source of dibenzocyclooctadiene lignans exhibiting potent activity.However,the functional role of PAL in the biosynthesis of lignan is relatively limited,compared with those in lignin and flavonoids biosynthesis.Therefore,it is essential to clone and characterize the PAL genes from this valuable medicinal plant.In this study,molecular cloning and characterization of three PAL genes(ScPAL1−3)from S.chinensis was carried out.ScPALs were cloned using RACE PCR.The sequence analysis of the three ScPALs was carried out to give basic characteristics followed by docking analysis.In order to determine their catalytic activity,recombinant protein was obtained by heterologous expression in pCold-TF vector in Escherichia coli(BL21-DE3),followed by Ni-affinity purification.The catalytic product of the purified recombinant proteins was verified using RP-HPLC through comparing with standard compounds.The optimal temperature,pH value and effects of different metal ions were determined.Vmax,Kcat and Km values were determined under the optimal conditions.The expression of three ScPALs in different tissues was also determined.Our work provided essential information for the function of ScPALs.展开更多
The adsorption isotherms of phenylalanine from aqueous solution on active carbon andsilica gel at varying pH,and the influence of inorganic salt upon the ad rption have been studied(at 25℃).The adsorption amount of p...The adsorption isotherms of phenylalanine from aqueous solution on active carbon andsilica gel at varying pH,and the influence of inorganic salt upon the ad rption have been studied(at 25℃).The adsorption amount of phcnylalanine on the silica gel is very low due to the strong ad-sorption of water by silica gel.The results on the active carbon show:(1)The adsorption is found to bepH-dependent,within pH 4.1—5.1 it increases with pH,within pH 5.1—11.8 it decreases with pH,atpH 5.1 the adsorption reaches its maximum;(2)The phenylalanine is adsorbed mainly in the formof zwitterion;(3)A certain amount of cations and anions of phenylalanine are also adsorbed with vander Waals interaction;(4)After adding NaCl,the adsorption of phenylalanine increases markedly.展开更多
The extraction behaviors of L-phenylalanine by di-( 2,4,4-trimethylpentyl) phosphinic acid , di-( 2,4,4-trimethylpentyl)- monothiophosphinic acid and di-(2-ethylhexyl) phosphoric acid were studied in both two-phase an...The extraction behaviors of L-phenylalanine by di-( 2,4,4-trimethylpentyl) phosphinic acid , di-( 2,4,4-trimethylpentyl)- monothiophosphinic acid and di-(2-ethylhexyl) phosphoric acid were studied in both two-phase and three-phase systems respectively. The equilibrium constants for these extraction reactions were calculated.展开更多
L-phenylalanine is an important aminoacid with biological activity.Man andanimal can not synthesize it themselvesand have to get it from the outsideworld.It is one of the eight indispens-able amino acids and also an
Phenylalanine in serum was determined by HPLC isotope dilution mass spectrometry method with D8 labeled phenylalanine as internal standard.Phenylalanine and its isotope labeled analogue were monitored at the transitio...Phenylalanine in serum was determined by HPLC isotope dilution mass spectrometry method with D8 labeled phenylalanine as internal standard.Phenylalanine and its isotope labeled analogue were monitored at the transitions m/z=166→120 and 172→126 in multiple reaction monitoring (MRM) mode,respectively,which effectively eliminated the matrix effect.The RSD for 5 repeats measurement of the same sample was 0.5%.Uncertainty was evaluated,which showed the main uncertainty was from the purity assessment of phenylalanine reference material and the variation of method.The presented method can be applied into value assessment of reference material of phenylalanine in serum,and it can be also used for traceability establishment of the measurement of phenylalanine in serum.展开更多
Sweetpotato[Ipomoea batatas(L.)Lam.],a food crop with both nutritional and medicinal uses,plays essential roles in food security and health-promoting.Chlorogenic acid(CGA),a polyphenol displaying several bioactivities...Sweetpotato[Ipomoea batatas(L.)Lam.],a food crop with both nutritional and medicinal uses,plays essential roles in food security and health-promoting.Chlorogenic acid(CGA),a polyphenol displaying several bioactivities,is distributed in all edible parts of sweetpotato.However,little is known about the specific metabolism of CGA in sweetpotato.In this study,IbPAL1,which encodes an endoplasmic reticulum-localized phenylalanine ammonia lyase(PAL),was isolated and characterized in sweetpotato.CGA accumulation was positively associated with the expression pattern of IbPAL1 in a tissue-specific manner,as further demonstrated by overexpression of IbPAL1.Overexpression of IbPAL1 promoted CGA accumulation and biosynthetic pathway genes expression in leaves,stimulated secondary xylem cell expansion in stems,and inhibited storage root formation.Our results support a potential role for IbPAL1 in sweetpotato CGA biosynthesis and establish a theoretical foundation for detailed mechanism research and nutrient improvement in sweetpotato breeding programs.展开更多
基金This study received financial support from the Youth Talents Special Project of Yunnan Province,“Xingdian Talents Support Program”(XDYC-QNRC-2022-0203)Southwest Forestry University Scientific Research Start-Up Funds(112116).
文摘Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus yunnanensis.In the present study,three PAL genes were cloned and identified from P.yunnanensis seedlings for thefirst time,namely,PyPAL-1,PyPAL-2,and PyPAL-3.Our results indicated that the open-reading frames of PyPAL genes were 2184,2157,and 2385 bp.Phylogenetic tree analysis revealed that PyPALs have high homology with other known PAL genes in other plants.In vitro enzymatic analysis showed that all three PyPAL recombinant proteins could catalyze the deamination of L-phenylalanine to form trans-cinnamic acid,but only PAL1 and PAL2 can catalyze the conversion of L-tyrosine toρ-coumaric acid.Three PyPAL genes were expressed in different tissues in 1-year-old P.yunnanensis,and such genes had different expression patterns.This study lays a foundation for further understanding of the biosynthesis of secondary metabolites in P.yunnanensis.
基金the grants fromthe National Natural Science Foundation of China(NNSF-30170663) the Chinese Academy of Sciences.
文摘Rhizopus rot of peach fruits could be significantly suppressed by Pichia membranefaciens.Polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonium-lyase (PAL) activities inducedby inoculation with P. membranefaciens or R. stolonifer were studied in postharvest peach fruits. The activ-ities of PPO and PAL in peaches increased significantly after being inoculated with P. membranefaciens + R.stolonifer by 24 h, the activities maintained at a high level throughout the experiment. Under the condition ofinfected with R. stolonifer alone, activity of PPO and PAL could also increased, but the levels were lowerthan those treated with P. membranefaciens+ R. stolonifer. However, fruits inoculaed with P. membrane-faciens+ R. stolonifer or R. stolonifer alone did not stimulated POD activity. The results suggest that theactivation of these defense enzymes is involved in the action of P. membranefaciens against R. stolonifer.
文摘Objective The aim is to ascertain whether phenylalanine (Phe) can inverse the left heart"remodeling" in patients with essential hypertension. Methods The changes of echocardiographic variables werecompared aler 3,6 and 9 months of observation between the Phe intervention group (Phe 1g/d+amiloride complex1 tablet/d, 20 cases) and control group (placebo 1g/d+amiloride complex 1 tablet/d, 20 cases) with eitherinterventricular septum and (or) post- wall thickness≥12mm, and were carried on further to compare incross- over trial. Results (1) Phe improved elfectively the left heart and systolic dyslunction; while theimprovement, also shown in control group due to the concurrent use of diuretic antihypertensive drug-amiloridecomplex, was much less evident than that in Phe group. (2) The disturbed left heart structure and systolic functionwere improved prominently while placebo was crossed over to Phe, and the improvement decreased afer Phe wascrrossed over to placebo. (3) The changes almost attained to its peak level after 6 months and not improved furtherat 9 months. (4) The differences seen between above 2 groops could not be eoplained by their diverse drops of bloodpressure. Conclusion Phe does exert an indopendent inverse effect on cardiac "remodeling", which mightimplicate an important clinical oplication upon the prevention and control of essential hypertension and itscomplications.
文摘The substrate hippuryl phenylalanine of carboxypeptidase A was selected as model to design new hapten molecule. N-Benzoyl tauryl phenylalanine (I) was synthesized and its structure was characterized by X-ray crystallography method.
基金supported by the National Natural Science Foundation of China(21825804,31921006)the National Science&Technology Major Project“Key New Drug Creation and Manufacturing Program”,China(2018ZX09711002-019)the Shanghai Municipal Science and Technology Major Project and the National Key Research and Development Program of China(2018YFA0800603)。
文摘Phenylketonuria(PKU),a disease resulting in the disability to degrade phenylalanine(Phe)is an inborn error with a 1 in 10,000 morbidity rate on average around the world which leads to neurotoxicity.As an potential alternative to a protein-restricted diet,oral intake of engineered probiotics degrading Phe inside the body is a promising treatment,currently at clinical stage II(Isabella,et al.,2018).However,limited transmembrane transport of Phe is a bottleneck to further improvement of the probiotic’s activity.Here,we achieved simultaneous degradation of Phe both intracellularly and extracellularly by expressing genes encoding the Phe-metabolizing enzyme phenylalanine ammonia lyase(PAL)as an intracellularly free and a cell surface-immobilized enzyme in Escherichia coli Nissle 1917(EcN)which overcomes the transportation problem.The metabolic engineering strategy was also combined with strengthening of Phe transportation,transportation of PAL-catalyzed trans-cinnamic acid and fixation of released ammonia.Administration of our final synthetic strain TYS8500 with PAL both displayed on the cell surface and expressed inside the cell to the Pah^(F263S)PKU mouse model reduced blood Phe concentration by 44.4%compared to the control Ec N,independent of dietary protein intake.TYS8500 shows great potential in future applications for PKU therapy.
基金supported by the National Natural Science Foundation of China (32225047,31922079)the Laboratory of Lingnan Modern Agriculture Project (NT2021005)。
文摘Emerging evidence suggests that amino acids dictate the effector functions of immune cells;however, whether and how phenylalanine(Phe) orchestrates the polarization of macrophages is not understood. Here, we determined that Phe attenuated lipopolysaccharide(LPS) and P. multocida serotype A strain CQ2(PmCQ2) infection-induced inflammation in vivo. Furthermore, we demonstrated that Phe inhibited the production of interleukin(IL)-1β and tumor necrosis factor(TNF)-α in proinflammatory(M1) macrophages. Phe reprogrammed the transcriptomic and metabolic profiles and enhanced oxidative phosphorylation in M1 macrophages, which reduced the activation of caspase-1. Notably, the valine-succinyl-CoA axis played a critical role in Phe-mediated inhibition of IL-1β production in M1 macrophages. Taken together, our findings suggest that manipulating the valine-succinyl-CoA axis provides a potential target for preventing and/or treating macrophage-related diseases.
文摘How plants produce the important defense hormone salicylic acid(SA)has been studied for almost 50 years.The current understanding is that in land plants,SA is biosynthesized from chorismate through the isochorismate(IC)pathway and the phenylalanine ammonia-lyase(PAL)pathway(Dempsey et al.,2011).
文摘With the method of synthesizing the L-phenylalanine by trans-cinnamic acid and ammonia in the presence of phenylalanine ammonialyase (PAL) under high pH and high concentration of cinnamic acid, it is not favorable for the conversion because of the deactivation of the PAL.For this reason, it is important to find out the suita-
文摘Background This study aimed to explore the value of applying a new pterin marker (isoxanthopterin) to the traditional urine pterin analysis to reduce the rate of mis-diagnosis of 6-pyruvoyltetrahydropterin synthase deficiency (PTPSD) and improve the accuracy of diagnosis.Methods We compared the urine neopterin (N),biopterin (B),isoxanthopterin (Iso),B% and Iso% levels between patients with phenylalanine hydroxylase deficiency and those with PTPSD,and found the most specific pterin biomarkers by ROC analysis.A positive cut-off value of urine pterins was determined.The effect of combined Iso% + B + B% in reducing PTPSD mis-diagnosis was evaluated,and the different urine pterin levels in PTPSD and false PTPSD (FPTPSD) were compared.The concordance of PTPSD diagnosis by the new pterin scheme and gene mutation analysis was determined.Results (1) Urinary B,B%,Iso and Iso% were significantly lower in PTPSD than those in phenylalanine hydroxylase-deficiency group (P < 0.01);(2) Iso%,B%,and B were the most specific markers;(3) The positive cut-off values of B,B%,Iso% for PTPSD were < 0.17 mmoL/moLCr,< 5.0%,and < 9.5%,respectively;(4) urinary B +B% + Iso% scheme significantly reduced the false-positive rate of PTPSD compared to traditional ones.The Iso% levels in FPTPSD group were higher than the ones in PTPSD group;(5) an accuracy of diagnosis for PTPSD was increased by 9-19% when Iso% was introduced to urinary pterin scheme.Conclusions Iso% is helpful to reduce the rate of misdiagnosis of PTPSD in the diagnosis by urinary pterin analysis for hyperphenylalaninemias and improve the accuracy of diagnosis.This approach is worthy of further development and increased utilization.
基金supported by the Natural Science Foundation of China(Nos.31100221 and 81325024)
文摘Phenolic compounds, metabolites of the phenylpropanoid pathway, play an important role in the growth and environmental adaptation of many plants. Phenylalanine ammonia-lyase(PAL) is the first key enzyme of the phenylpropanoid pathway. The present study was designed to investigate whether there is a multi-gene family in I. Indigotic and, if so, to characterize their properties. We conducted a comprehensive survey on the transcription profiling database by using tBLASTn analysis. Several bioinformatics methods were employed to perform the prediction of composition and physicochemical characters. The expression levels of IiPAL genes in various tissues of I. indigotica with stress treatment were examined by quantitative real-time PCR. Protoplast transient transformation was used to observe the locations of IiPALs. IiPALs were functionally characterized by expression with pET-32a vector in Escherichia colis strain BL21(DE3). Integration of transcripts and metabolite accumulations was used to reveal the relation between IiPALs and target compounds. An new gene(IiPAL2) was identified and both IiPALs had the conserved enzymatic active site Ala-Ser-Gly and were classified as members of dicotyledon. IiPAL1 and IiPAL2 were expressed in roots, stems, leaves, and flowers, with the highest expression levels of IiPAL1 and IiPAL2 being observed in stems and roots, respectively. The two genes responded to the exogenous elicitor in different manners. Subcellular localization experiment showed that both IiPALs were localized in the cytosol. The recombinant proteins were shown to catalyze the conversion of L-Phe to trans-cinnamic acid. Correlation analysis indicated that Ii PAL1 was more close to the biosynthesis of secondary metabolites than IiPAL2. In conclusion, the present study provides a basis for the elucidation of the role of Ii PALs genes in the biosynthesis of phenolic compounds, which will help further metabolic engineering to improve the accumulation of bioactive components in I.indigotica.
文摘A polymer with suitable physical characters and matched functional groups was synthesized,and used as a supporter to immobilize aminoacylase. The results showed that this supporterhad high immobilizing capacity and high selectivity for aminoacylase. Immobilized amino-acylase had high specific activity. In this paper, we determine the physical and chemicalcharacters of aminoacylase for resolution of D,L--phenylalanine, including its optimum tem-perature, pH, ion concentration, activated ion, substrate concentration, thermal stability anddenaturation. The immobilized aminoacylase was used to resolve the D,L-phenylalaninecontinuously. Thc resolved products was separated and purified with ion-exchange resins. L-phenylalanine solution was concentrated by vacuum evaporation and its hydrochloride wasformed. Checking of final product with polarimeter showed high yield and purity.
文摘It is well known that salinity has badly effect on plant growth all over the world and greatly reduces crop production in the affected regions.Selenium can function as an antioxidant in plants and also in low concentration can promotes plant growth and produce tolerance against stress.This study was conducted in order to determine the effects of selenium(Se)application(0,4,8 and 16 mg L^-1)on phenylalanine ammonia-lyase(PAL)activity,phenol leakage and total phenolic content of garlic under salt stress(0,30,60 and 90 mM NaCl).The highest PAL activity was recorded at 60 and 90 mM NaCl salinity with application of 8mg Se L^-1.Also,when Se was added to the salt-stress garlic,the level of phenol leakage was decreased significantly at two levels of NaCl concentration(by 52%and 40%at 30 mM NaCl with application of 4 and 16 mg Se L^-1,and by 50%at 90 mM NaCl with application of 4mg Se L^-1,respectively)in comparison to the salt-stressed garlic without Se.The results showed that Se can increase the salt tolerance of garlic by protecting the cell membrane against lipid peroxidation.The highest concentration of phenols was recorded at 90 mM NaCl salinity level with application of 4 and 8 mg Se L^-1,that respectively produced 59%and 51%higher phenols than control treatment without Se.So,application of optimal Se level can increase the potential of garlic in a medium with relatively high level of NaCl.
文摘In the development of new peptide drugs, it is an important way to synthesize the analogs of bioactive peptide. There are different methods to obtain the analogs, including: (ⅰ) changing the backbond structure of a peptide; (ⅱ) changing the amino acid residues and (ⅲ) introducing D-amino acids into a peptide. In some cases, to get high potent analogs of a peptide, unnatural amino acids are needed.
基金supported by the National Key R&D Program of China(No.2017YFC1701200).
文摘Phenylalanine ammonia-lyase(PAL),which catalyzes the conversion from L-phenylalanine to trans-cinnamic acid,is a well-known key enzyme and a connecting step between primary and secondary metabolisms in the phenylpropanoid biosynthetic pathway of plants and microbes.Schisandra chinensis,a woody vine plant belonging to the family of Magnoliaceae,is a rich source of dibenzocyclooctadiene lignans exhibiting potent activity.However,the functional role of PAL in the biosynthesis of lignan is relatively limited,compared with those in lignin and flavonoids biosynthesis.Therefore,it is essential to clone and characterize the PAL genes from this valuable medicinal plant.In this study,molecular cloning and characterization of three PAL genes(ScPAL1−3)from S.chinensis was carried out.ScPALs were cloned using RACE PCR.The sequence analysis of the three ScPALs was carried out to give basic characteristics followed by docking analysis.In order to determine their catalytic activity,recombinant protein was obtained by heterologous expression in pCold-TF vector in Escherichia coli(BL21-DE3),followed by Ni-affinity purification.The catalytic product of the purified recombinant proteins was verified using RP-HPLC through comparing with standard compounds.The optimal temperature,pH value and effects of different metal ions were determined.Vmax,Kcat and Km values were determined under the optimal conditions.The expression of three ScPALs in different tissues was also determined.Our work provided essential information for the function of ScPALs.
文摘The adsorption isotherms of phenylalanine from aqueous solution on active carbon andsilica gel at varying pH,and the influence of inorganic salt upon the ad rption have been studied(at 25℃).The adsorption amount of phcnylalanine on the silica gel is very low due to the strong ad-sorption of water by silica gel.The results on the active carbon show:(1)The adsorption is found to bepH-dependent,within pH 4.1—5.1 it increases with pH,within pH 5.1—11.8 it decreases with pH,atpH 5.1 the adsorption reaches its maximum;(2)The phenylalanine is adsorbed mainly in the formof zwitterion;(3)A certain amount of cations and anions of phenylalanine are also adsorbed with vander Waals interaction;(4)After adding NaCl,the adsorption of phenylalanine increases markedly.
文摘The extraction behaviors of L-phenylalanine by di-( 2,4,4-trimethylpentyl) phosphinic acid , di-( 2,4,4-trimethylpentyl)- monothiophosphinic acid and di-(2-ethylhexyl) phosphoric acid were studied in both two-phase and three-phase systems respectively. The equilibrium constants for these extraction reactions were calculated.
文摘L-phenylalanine is an important aminoacid with biological activity.Man andanimal can not synthesize it themselvesand have to get it from the outsideworld.It is one of the eight indispens-able amino acids and also an
文摘Phenylalanine in serum was determined by HPLC isotope dilution mass spectrometry method with D8 labeled phenylalanine as internal standard.Phenylalanine and its isotope labeled analogue were monitored at the transitions m/z=166→120 and 172→126 in multiple reaction monitoring (MRM) mode,respectively,which effectively eliminated the matrix effect.The RSD for 5 repeats measurement of the same sample was 0.5%.Uncertainty was evaluated,which showed the main uncertainty was from the purity assessment of phenylalanine reference material and the variation of method.The presented method can be applied into value assessment of reference material of phenylalanine in serum,and it can be also used for traceability establishment of the measurement of phenylalanine in serum.
基金supported by the National Key Research and Development Program of China(2019YFD1001302 and 2019YFD1001300)National Natural Science Foundation of China(31701483 and 31601382)+2 种基金Jiangsu Agricultural Science and Technology Independent Innovation Fund[CX(19)3063]the National Technical System of Sweetpotato Industry(CARS-10-C3)Jiangsu Province Science and Technology Support Program(BK20171325)。
文摘Sweetpotato[Ipomoea batatas(L.)Lam.],a food crop with both nutritional and medicinal uses,plays essential roles in food security and health-promoting.Chlorogenic acid(CGA),a polyphenol displaying several bioactivities,is distributed in all edible parts of sweetpotato.However,little is known about the specific metabolism of CGA in sweetpotato.In this study,IbPAL1,which encodes an endoplasmic reticulum-localized phenylalanine ammonia lyase(PAL),was isolated and characterized in sweetpotato.CGA accumulation was positively associated with the expression pattern of IbPAL1 in a tissue-specific manner,as further demonstrated by overexpression of IbPAL1.Overexpression of IbPAL1 promoted CGA accumulation and biosynthetic pathway genes expression in leaves,stimulated secondary xylem cell expansion in stems,and inhibited storage root formation.Our results support a potential role for IbPAL1 in sweetpotato CGA biosynthesis and establish a theoretical foundation for detailed mechanism research and nutrient improvement in sweetpotato breeding programs.
