氨基酸对中华绒螯蟹N-乙酰-β-D-氨基葡萄糖苷酶活力的影响

Effects of Amino Acids on N-acetyl-β-D-glucosaminidase Activity of Eriocheir sinensis

研究了12种氨基酸对中华绒螯蟹(Eriocheir sinensis)N-乙酰-β-D-氨基葡萄糖苷酶活力的影响.结果表明,在特定浓度范围内,甘氨酸(L-Gly)、缬氨酸(L-Val)、丙氨酸(L-Ala)、苯丙氨酸(L-Phe)、苏氨酸(L-Thr)和丝氨酸(L-Ser)对酶活力没有显著影响,而蛋氨酸(L-Met)、天冬酰胺(L-Gln)、脯氨酸(L-Pro)、精氨酸(L-Arg)、组氨酸(L-His)和赖氨酸(L-Lys)对酶活力有不同程度的抑制作用.L-Pro、L-Arg和L-Lys使酶活力下降50%时抑制剂浓度(IC50)分别为450、20、85mmolL-1.L-Pro对酶的抑制表现为可逆非竞争性类型,对酶的抑制常数KI为702.87mmolL-1.L-Arg、L-His和L-Lys对酶的抑制均表现为可逆反竞争性类型,对酶的抑制常数KIS分别为2.19、85.81、10.23mmolL-1.

The effects of 12 kinds of amino acids on the activity of N-acetyl-β-D-glucosaminidase from Eriocheir sinensis were studied. The results showed that L-Gly, L-Val, L-Thr, L-Ala, L-Phe and L-Ser had not any effects on the enzyme activity in the tested range of concentration. The enzyme activity was inhibited by L-Met, L-Gln, L-Pro, L-Arg, L-His and L-Lys to some extent. L-Gln and L-Met can reduce the enzyme activity slightly. The inhibitor concentrations （IC50） of L-Pro, L-Arg and L-Lys, which made the enzyme activity reduced by 50%, were 450, 20 and 85 mmol L^-1, respectively. L-Pro was reversible non-competitive inhibitor. The inhibition constant （KI） of L-Pro to free enzyme was 702.87 mmol L^-1. L-Arg, L-His and L-Lys were reversible non-competitive inhibitors. The inhibition constants （KIS） of L-Arg, L-His and L-Lys to free enzyme were 2.19, 85.81 and 10.23 mmol L^-1, respectively. Fig 9, Ref 10