BIOSYNTHESIS OF PORPHYRINS IN WHEAT LEAVES: I. SUCCINATE:CoA LIGASE (ADP)

Succinate:CoA ligase (ADP) (E.C. No. 6.2.1.5) was isolated and partially purified from acetone powders of wheat leaves. The enzyme is specific for succinate and ATP, but is inhibited by concentrations of ATP above 4.5 × 10−3 M and requires either Mg++or Mn++ions. Kmvalues for succinate, ATP, CoA, Mg++, and MH++are 3.2 × 10−2 M, 1.3 × 10−3 M, 9.5 × 10−5 M, 4.1 × 10−3 M, and 3.7 × 10−3 M respectively. The enzyme is localized within chloroplasts and catalyzes a termolecular reaction.