节杆菌LF-Tou2葡萄糖基转移酶是控制絮凝剂聚糖合成的酶。通过对细胞超声破碎使酶释放,经Sephadex G200凝胶色谱和DEAE-Sepharose Fast Flow离子交换色谱对酶进行了纯化。对酶学特性进行了分析,并用5种化学修饰剂对酶分子中5种不同氨基...节杆菌LF-Tou2葡萄糖基转移酶是控制絮凝剂聚糖合成的酶。通过对细胞超声破碎使酶释放,经Sephadex G200凝胶色谱和DEAE-Sepharose Fast Flow离子交换色谱对酶进行了纯化。对酶学特性进行了分析,并用5种化学修饰剂对酶分子中5种不同氨基酸残基与催化活性之间的关系进行了研究。结果表明:该酶的分子质量为14315Da;样品中w(α-螺旋)=31.7%,w(β-转角)=34.1%,w(无规卷曲)=34.2%。Km为2.752μmol,Vmax为58.056μmol/min;Mn2+是酶活性强有力的激活剂,Fe2+次之。酪氨酸和二硫键是酶分子的结构基团,色氨酸、巯基和组氨酸是酶活力的必需基团,在必需基团中色氨酸最关键。展开更多
Tax payers and tax administrators are the main structural groups in tax system. They interact and have an impact on each other＇s actions following by tax compliance or tax non-compliance. However, no wider study enco...Tax payers and tax administrators are the main structural groups in tax system. They interact and have an impact on each other＇s actions following by tax compliance or tax non-compliance. However, no wider study encompassing both tax payers and tax administrators has been conducted in Lithuania. Since a survey of all participants in the tax system would require substantial time, human, and financial resources, during the first study, only one group, tax payers, was surveyed. During the second study, tax administrators were surveyed along with the tax payers. The present study has the following objectives： to describe the problem of tax evasion in the context of attitudes and behaviours of participants in the tax system; to estimate the tax compliance and evasion situation in Lithuania on the basis of attitudes and behaviours of tax payers; to establish how tax administrators estimate the tax compliance （evasion） situation in Lithuania; to assess the relationship between tax administrators and tax payers; to determine similarities and differences of their attitudes; to assess the key aspects of tax evasion; and to identify measures for the solution of this problem.展开更多
Chemical stability and reactivity of organic pollutants is dependent to their formation enthalpies. The main objective of this study is to provide simple straightforward strategy for prediction of the formation enthal...Chemical stability and reactivity of organic pollutants is dependent to their formation enthalpies. The main objective of this study is to provide simple straightforward strategy for prediction of the formation enthalpies of wide range organic pollutants only from their structural functional groups. Using such an extended dataset cornprising 1694 organic chemicals from 77 diverse material classes benefits the generalizability and reliability of the study. The new suggested collection of 12 functional groups and a simple linear regression lead to promising statis- tics of R2= 0.958, Q2 =0.956, and AEE= 57 kJ.mo1-1 for the whole dataset. Moreover, unknown experimental formation enthalpies for 27 organic pollutants are estimated by the presented approach. The resultant model needs no technical software/calculations, and thus can be easily applied by a non-specialist user.展开更多
文摘节杆菌LF-Tou2葡萄糖基转移酶是控制絮凝剂聚糖合成的酶。通过对细胞超声破碎使酶释放,经Sephadex G200凝胶色谱和DEAE-Sepharose Fast Flow离子交换色谱对酶进行了纯化。对酶学特性进行了分析,并用5种化学修饰剂对酶分子中5种不同氨基酸残基与催化活性之间的关系进行了研究。结果表明:该酶的分子质量为14315Da;样品中w(α-螺旋)=31.7%,w(β-转角)=34.1%,w(无规卷曲)=34.2%。Km为2.752μmol,Vmax为58.056μmol/min;Mn2+是酶活性强有力的激活剂,Fe2+次之。酪氨酸和二硫键是酶分子的结构基团,色氨酸、巯基和组氨酸是酶活力的必需基团,在必需基团中色氨酸最关键。
文摘Tax payers and tax administrators are the main structural groups in tax system. They interact and have an impact on each other＇s actions following by tax compliance or tax non-compliance. However, no wider study encompassing both tax payers and tax administrators has been conducted in Lithuania. Since a survey of all participants in the tax system would require substantial time, human, and financial resources, during the first study, only one group, tax payers, was surveyed. During the second study, tax administrators were surveyed along with the tax payers. The present study has the following objectives： to describe the problem of tax evasion in the context of attitudes and behaviours of participants in the tax system; to estimate the tax compliance and evasion situation in Lithuania on the basis of attitudes and behaviours of tax payers; to establish how tax administrators estimate the tax compliance （evasion） situation in Lithuania; to assess the relationship between tax administrators and tax payers; to determine similarities and differences of their attitudes; to assess the key aspects of tax evasion; and to identify measures for the solution of this problem.
基金Supported by the "Tehran Naftoon Arya Eng. Co." research committee of Iran
文摘Chemical stability and reactivity of organic pollutants is dependent to their formation enthalpies. The main objective of this study is to provide simple straightforward strategy for prediction of the formation enthalpies of wide range organic pollutants only from their structural functional groups. Using such an extended dataset cornprising 1694 organic chemicals from 77 diverse material classes benefits the generalizability and reliability of the study. The new suggested collection of 12 functional groups and a simple linear regression lead to promising statis- tics of R2= 0.958, Q2 =0.956, and AEE= 57 kJ.mo1-1 for the whole dataset. Moreover, unknown experimental formation enthalpies for 27 organic pollutants are estimated by the presented approach. The resultant model needs no technical software/calculations, and thus can be easily applied by a non-specialist user.
