Catalytic Properties of X-Prolyl Dipeptidyl Aminopeptidase from<i>Lactococcus lactis</i>subsp.<i>cremoris</i>nTR
作者:Tsong-Rong Yan、Shih-Ching Ho、Chia-Lung Hou
DOI:10.1271/bbb.56.704
日期:1992.1
An X-prolyl dipeptidyl aminopeptidase (X-PDAP; EC 3.4.14.5) was identified to be loosely bound on the inner cell membrane fraction of Lactococcus lactis subsp. cremoris nTR. The biosynthesis of X-PDAP was continuously increased before the late-log growth phase of the bacteria. Both Gly-Pro-pNA and Ala-Ala-pNA were hydrolyzed by X-PDAP; the kcat/Km value of the former was about 10-fold that of the latter. The Ki of X-Pro and Pro-X were more specific to X-PDAP than those of X-Ala. The enzyme splitting a dipeptide sequentially from β-casomorphin as a model catalytic pattern was identified and some properties of the enzyme were further characterized.
在Lactococcus lactis subsp. cremoris nTR的内细胞膜组分上,鉴定出一种松散结合的X-脯氨酰二肽二肽基氨肽酶(X-PDAP;EC 3.4.14.5)。在细菌的后期对数生长阶段之前,X-PDAP的生物合成不断增加。X-PDAP可以水解Gly-Pro-pNA和Ala-Ala-pNA,前者的kcat/Km值约为后者的10倍。X-Pro和Pro-X的Ki比X-Ala更特异于X-PDAP。鉴定出一种以β-酪啡肽为模型的催化模式连续切割二肽的酶,并进一步表征了该酶的一些性质。