期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：1997
卷号：43
期号：2
页码：177-186
DOI：10.3177/jnsv.43.177
出版社：Center for Academic Publications Japan
摘要：Cobalamin-dependent methionine synthase was purified from rat liver. The enzyme activity was separated into two peaks upon Mono-Q column chromatography. Peaks I and II of the enzyme, eluted in this order, were purified 18, 000- and 44, 000-fold in overall yields of 0.7 and 1.8%, respectively. Peak II methionine synthase, the major fraction, was homogeneous as judged by SDS-polyacrylamide gel electrophoresis. The enzyme was a large monomeric protein with an apparent molecular weight of 143, 000 Da. Interconversion of the enzyme between the two peaks was not observed during purification procedures. The enzyme required S adenosylmethionine and a reducing system for activity. Ap-parent Km values of the peak II enzyme for 5-methyltetrahydrofolate and homocysteine were 75 and 1.7μM, respectively.
