Heincz M C, McFall E
J Bacteriol. 1976 Apr;126(1):132-9. doi: 10.1128/jb.126.1.132-139.1976.
The primary D-serine deaminase (D-serine dehydratase, EC 4.2.1.14) of Escherichia coli K-12 is unstable within the cell. The protein, a single polypeptide chain, is cleaved at a lysine residue by a cellular proteolytic activity. Fragments containing the active site then aggregate into tetramers, which retain substrate affinity and show very low catalytic activity. Such degradations may represent an evolutionary mechanism for the generation of new enzymes.
大肠杆菌K-12的主要D-丝氨酸脱氨酶(D-丝氨酸脱水酶,EC 4.2.1.14)在细胞内不稳定。该蛋白质为单条多肽链,会被细胞内的蛋白水解活性在一个赖氨酸残基处切割。含有活性位点的片段随后聚合成四聚体,这些四聚体保留底物亲和力并显示出非常低的催化活性。这种降解可能代表了产生新酶的一种进化机制。