关于博伊丁假丝酵母中甲醇异化途径的一种酶——S-甲酰谷胱甘肽水解酶的研究。

Studies on an enzyme, S-formylglutathione hydrolase, of the dissimilatory pathway of methanol in Candida boidinii.

作者信息

Neben I, Sahm H, Kula M R

出版信息

Biochim Biophys Acta. 1980 Jul 10;614(1):81-91. doi: 10.1016/0005-2744(80)90169-2.

Abstract

In Candida boidinii, S-formylglutathione formed by reaction of the glutathione-dependent formaldehyde dehydrogenase is hydrolyzed to formate and glutathione by a special enzyme, S-formylglutathione hydrolase which is induced in C. boidinii along with the other enzymes of the dissimilatory pathway during growth on CH3OH. The S-formylglutathione hydrolase was purified to apparent homogeneity and a specific activity of 1390 U/mg. The molecular weight of the native enzyme was determined as 61 000 by gel filtration and 64 000 by sedimentation-diffusion equilibrium. It is composed of two nonidentical polypeptide chains of 35 000 and 25 000 daltons. The Km-value of S-formylglutathione was found to be 0.21 mM. Glutathione is a competitive inhibitor with a Ki vaue of 18.5 mM. The enzyme is very specific for S-formylglutatione, S-acetylglutathione gave 1.3%, respectively. Other glutathione derivatives of hydroxyacids tested were not split by the S-formylglutatione hydrolase.

摘要

在博伊丁假丝酵母中，由谷胱甘肽依赖性甲醛脱氢酶反应形成的S-甲酰谷胱甘肽，会被一种特殊的酶——S-甲酰谷胱甘肽水解酶水解为甲酸和谷胱甘肽。在甲醇上生长期间，该酶在博伊丁假丝酵母中与异化途径的其他酶一起被诱导产生。S-甲酰谷胱甘肽水解酶被纯化至表观均一，比活性为1390 U/mg。通过凝胶过滤测定天然酶的分子量为61000，通过沉降扩散平衡测定为64000。它由两条不同的多肽链组成，分子量分别为35000和25000道尔顿。发现S-甲酰谷胱甘肽的Km值为0.21 mM。谷胱甘肽是一种竞争性抑制剂，Ki值为18.5 mM。该酶对S-甲酰谷胱甘肽具有高度特异性，S-乙酰谷胱甘肽的水解率分别为1.3%。测试的其他羟基酸谷胱甘肽衍生物均不能被S-甲酰谷胱甘肽水解酶裂解。