Purification and characterization of methylmalonyl-CoA mutase from Ascaris lumbricoides

Methylmalonyl CoA mutase from Ascaris lumbricoides has been purified to homogeneity. The mutase is homogeneous as judged by equilibrium sedimentation and polyacrylamide gel electrophoresis. The worm mutase is a glycoprotein with a mol. wt of 147,000 +/- 3500 composed of two identical or very similar subunits. One molecule of adenosylcobalamin is tightly bound to each subunit. The mutase from Ascaris is not affected by exposure to light, cyanide ion or intrinsic factor and is not inhibited by iodoacetate and rho-hydroxymercuribenzoate. The kinetic constants of this mutase for (R,S)methylmalonyl CoA are Km = 4.2 X 10(-5) M and Vmax = 4.73 mumol/mg/min.