Abstract
An acetate-independent, pyruvate kinase-positive revertant, m 570 R 3 a, was obtained from an acetate-requiring, pyruvate kinase-negative ace-8 mutant strain. This revertant appears to be derived from a secondary mutation in the ace-8 gene. Ion-exchange chromatography of the extracts from both the wild type strain, KGa, and the revertant strain, m 570 R 3 a, shows that pyruvate kinases of these strains are different in electric charge. This was confirmed by polyacrylamide gel electrophoresis of these two samples. The Km values of the enzyme from both strains for the substrate, phosphoenolpyruvate, are also different. Molecular weight of the subunit of pyruvate kinase from both strains was the same and estimated as 65, 000 by SDS-polyacrylamide gel elecrophoresis with gradient concentrations of 8-25% polyacrylamide. These data show that pyruvate kinase of the revertant strain is qualitatively different from that of the wild type strain, and suggest that the ace-8 gene is the structural gene of pyruvate kinase of Neurospora crassa.
