Marsh E N, Harding S E, Leadlay P F
Department of Biochemistry, University of Cambridge, U.K.
Biochem J. 1989 Jun 1;260(2):353-8. doi: 10.1042/bj2600353.
The effect of increasing ionic strength on adenosylcobalamin-dependent methylmalonyl-CoA mutase from Propionibacterium shermanii was studied by using analytical ultracentrifugation. Both sedimentation-velocity and low-speed sedimentation-equilibration measurements show that the enzyme dissociates progressively into its two dissimilar subunits with increasing ionic strength. Equilibrium between the alpha beta-dimer and the separated subunits is rapidly established under these conditions. Dissociation is accompanied by loss of enzymic activity, but the position of the equilibrium is unaffected by the presence of either substrate or adenosylcobalamin cofactor.
通过分析超速离心法研究了增加离子强度对谢氏丙酸杆菌中腺苷钴胺素依赖性甲基丙二酰辅酶A变位酶的影响。沉降速度和低速沉降平衡测量均表明，随着离子强度的增加，该酶逐渐解离成两个不同的亚基。在这些条件下，αβ-二聚体与分离的亚基之间能迅速建立平衡。解离伴随着酶活性的丧失，但平衡位置不受底物或腺苷钴胺素辅因子存在的影响。
