Baker’s yeast UMP:pyrophosphate phosphoribosyltransferase (EC 2.4.2.9) has been extensively purified and the final preparation seemed to be pure but not homogeneous. The native enzyme showed a molecular weight of 80,000 calculated by gel filtration; disc gel electrophoresis performed in the presence of sodium dodecyl sulfate and reducing agents showed two dissimilar subunits and the sum of thei...
