期刊
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY
卷 65, 期 4, 页码 865-874出版社
TAYLOR & FRANCIS LTD
DOI: 10.1271/bbb.65.865
关键词
serine acetyltransferase; cysteine synthetase; enzyme complex; cold inactivation; proteolysis
Cysteine synthetase from Escherichia coli is a bienzyme complex composed of serine acetyltransferase (SAT) and O-acetylserine sulfhydrylase-A, (OASS), The effects of the complex formation on the stability of SAT against cold inactivation and proteolysis were investigated. SAT was reversibly inactivated on cooling to 0 degreesC. Ultracentrifugal analysis showed that SET (a hexamer) was dissociated mostly into two trimers on cooling to 0 degreesC in the absence of OASS, while in the presence of BASS one trimer of the SAT subunits formed a complex with one dimer of BASS subunits. In the presence of BASS, trot only the cold inactivation rate was reduced but also the reactivation rate was increased. Furthermore, SAT became stable against proteolytic attack bg alpha -chymotrypsin and V8 protease by forming the complex with OASS, On the other hand, SAT was degraded by trypsin in the same manner both in the presence and in the absence of OASS. The different tendency in the stability against proteolysis with the different proteases was discussed with respect to the substrate specificity of the proteases and amino acid sequence of the C-terminal region of SAT that interacts with OASS.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据