Leadlay P F
Biochem J. 1981 Aug 1;197(2):413-9. doi: 10.1042/bj1970413.
Methylmalonyl-CoA epimerase, which specifically interconverts the (2R)- and (2S)- epimers of methylmalonyl-CoA, was purified 95-fold from Propionibacterium shermanii by a new method that affords apparently homogeneous enzyme, in 80-100mg quantities, in yields representing about 40% of the activity in cell-free extracts. The specific activity of the purified enzyme, 10.1 mukat/mg, is much greater than previously reported. Native methylmalonyl-CoA epimerase has Mr about 33000, and apparently consists of two identical subunits. The purified enzyme is stable indefinitely when stored at -20 degrees C and pH 8.5, but contrary to previous reports it is not unusually acid-stable. The activity of methylmalonyl-CoA epimerase is increased by Co2+, and to a smaller extent by Ni2+, Mn2+ and Zn2+.
甲基丙二酰辅酶A差向异构酶能特异性地使甲基丙二酰辅酶A的(2R)-和(2S)-差向异构体相互转化。采用一种新方法从谢氏丙酸杆菌中纯化该酶，纯化倍数达95倍。此方法能获得明显均一的酶，产量为80 - 100毫克，产率约为无细胞提取物中活性的40%。纯化后酶的比活性为10.1微卡特/毫克，远高于先前报道。天然甲基丙二酰辅酶A差向异构酶的分子量约为33000，显然由两个相同的亚基组成。纯化后的酶在-20℃和pH 8.5条件下可无限期稳定保存，但与先前报道相反，它并非异常耐酸。甲基丙二酰辅酶A差向异构酶的活性可被Co2+增强，Ni2+、Mn2+和Zn2+在较小程度上也有增强作用。
