title: Subunit interactions in Propionibacterium shermanii methylmalonyl-CoA mutase studied by analytical ultracentrifugation.
abstract: 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.
authors.affiliation: Department of Biochemistry, University of Cambridge, U.K.
authors.forename: E N
authors.initials: EN
authors.lastname: Marsh
authors.forename: S E
authors.initials: SE
authors.lastname: Harding
authors.forename: P F
authors.initials: PF
authors.lastname: Leadlay
mesh_terms: D000214:Acyl Coenzyme A; D000645:Ammonium Sulfate / Q000378:metabolism; D007535:Isomerases / Q000378:metabolism*; D008316:Malonyl Coenzyme A / Q000031:analogs & derivatives; D008765:Methylmalonyl-CoA Mutase / Q000378:metabolism*; D008968:Molecular Conformation; D008970:Molecular Weight; D011424:Propionibacterium / Q000201:enzymology*; D014461:Ultracentrifugation
chemical_list: D000214:Acyl Coenzyme A; C015357:methylmalonyl-coenzyme A; D008316:Malonyl Coenzyme A; D007535:Isomerases; D008765:Methylmalonyl-CoA Mutase; D000645:Ammonium Sulfate