The metabolism of [14C]bicarbonate byStreptococcus lactis: the fixation of [14C]bicarbonate by pyruvate carboxylase

Abstract

SummaryThe fixation of [14C]bicarbonate into aspartate byStreptococcus lactisC10 was achieved by the combined reactions of pyruvate carboxylase (E.C. 6.4.1.1) and glutamate-oxaloacetate transaminase (E.C. 2.6.1.1). The pyruvate carboxylase fromStr. lactisC10, which was most active at pH 8·0, was activated by the divalent metal ions Mn2+, Mg2+and Co2+, and inhibited by sulphydryl reagents. The enzyme was inhibited non-competitively by aspartic acid and competitively by oxaloacetate.