摘要
本研究旨在进一步挖掘牦牛奶渣酪蛋白潜在的α-葡萄糖苷酶抑制活性。以牦牛奶渣酪蛋白为肽源,利用生物信息学NCBI蛋白在线数据库,对其牦牛奶渣酪蛋白氨基酸序列进行检索。并采用EXPASY中的pdecutteepti工具,对检索到的每条牦牛奶渣酪蛋白氨基酸序列进行模拟酶切,获得预测蛋白酶分别为胃蛋白酶和胰蛋白酶。以α-葡萄糖苷酶作为抑制率指标,采用5种蛋白酶进行综合验证。确定采用胃蛋白酶和胰蛋白酶两者为最佳适用蛋白酶,与模拟酶切预测结果一致。经过两步酶解单因素和响应面优化实验,研究酶解时间和加酶量对α-葡萄糖苷酶抑制率的影响。以α-葡萄糖苷酶抑制率为评价抑制活性的重要指标,最佳两种蛋白酶的酶解结果为:胃蛋白酶酶解时间为150 min,胰蛋白酶酶解时间为240 min。胃蛋白酶和胰蛋白加酶量分别为300 U/g和700 U/g。在此条件下的α-葡萄糖苷酶抑制率为72%。最后采用液质联用鉴定多肽序列。结果表明胃蛋白酶和胰蛋白酶经两步酶解后产生的酪蛋白酶解液,具有良好的α-葡萄糖苷酶抑制活性,为制备食源性α-葡萄糖苷酶抑制提供了新的研究策略。
This study was to further explore the potentialα-glucosidase inhibitory activity of yak milk residue casein.Using the yak milk residue casein as the peptide source,the amino acid sequence of the yak milk residue casein was searched by the NCBI protein online database of bioinformatics.Using the pdecutteepti tool in EXPASY,the amino acid sequence of each yak milk residue casein amino acid sequence retrieved was simulated by digestion,and the predicted proteases were pepsin and trypsin respectively.Taking α-glucosidase as an indicator of the inhibition rate,five proteases were used for comprehensive verification.It was determined that both pepsin and trypsin were the best suitable proteases,which was consistent with the predicted results of simulated enzyme digestion.After two-step enzymatic hydrolysis single factor and response surface optimization experiments,the effect of enzymatic hydrolysis time and the amount of enzyme added on the inhibition rate ofα-glucosidase was studied.Taking the inhibition rate ofα-glucosidase as an important indicator to evaluate the inhibitory activity,the best two protease digestion results were that pepsin digestion time was 150 min,and trypsin digestion time was 240 min.The amounts of pepsin and trypsin plus enzyme were 300 U/g and 700 U/g,respectively.Under these conditions,the inhibitory rate ofα-glucosidase was 72%.Finally,liquid-mass spectrometry was used to identify the peptide sequence.All in all,the casein hydrolysate produced by the two-step enzymatic hydrolysis of pepsin and trypsin had good inhibitory activity of glucosidase,which provided a new research strategy for the preparation of food-borne glucosidase inhibitors.
作者
史加加
罗章
SHI Jiajia;Luo Zhang(Food Science College,Tibet Agriculture&Animal Husbandry university,Nyingch Tibet,860000,China)
出处
《高原农业》
2021年第4期402-413,共12页
Journal of Plateau Agriculture
基金
西藏农牧学院研究生教育创新计划项目(YJS2020-37)。
关键词
牦牛奶渣
酪蛋白
酶解
响应面优化
α-葡萄糖苷酶抑制率
Yak milk residue
caseine
enzymatic hydrolysis
response surface optimization
α-glucosidase inhibition rate
