摘要
以丙酮为效应物,研究其对黄粉虫(Tenebrio molitor Linnaeus)N-乙酰-β-D-氨基葡萄糖苷酶(NAGase)活力的影响,结果表明该酶的剩余活力随着丙酮浓度增大而呈指数下降。导致酶活力丧失50%(抑制半衰期,IC50)的丙酮浓度为7.2%,说明丙酮对黄粉虫NAGase有明显的失活作用。该酶的失活过程属于混合型,并进一步测定游离酶(E)和酶底物络合物(ES)与丙酮的结合常数(KI和KIS),分别为5.32%和27.2%,KI<KIS,说明底物存在对酶被丙酮的失活作用有一定的保护作用。
The effects of acetone on activity of N-acetyl-β-D-glucosaminidase （NAGase） from Tenebrio molitor Linnaeus were investigated. The results showed that the remaining enzyme activity rapidly declines with increasing of acetone concentrations. The enzyme activity remained 5% while acetone concentration（VN） reached 40%, which suggested the acetone makes the enzyme inactivate obviously. Acetone concentration leading to 50% activity lost （repress halflife, IC50） is estimated to be 7.2%. The inactivation of enzyme by lower concentration of acetone （〈 10%） is a reversible reaction with remaining enzyme activity. The kinetics analysis of inactivation showed that the inactivation of the enzyme in acetone solutions is of mix-competitive type. The combinative constants （IG and KIS） of the free enzyme and the enzyme-substrate complex are determined to be 5.32% and 27.2%, respectively. The value of KIS is larger than that of K1, indicating a marked protective effect of the substrate on the inactivation of the enzyme.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2007年第6期233-236,共4页
Food Science
基金
泉州师范学院重点学科资助项目(XK0609)
