Properties of Ornithine Carbamoyltransferase from Pisum sativum L

Abstract

Some properties of ornithine carbamoyltransferase from chloroplasts isolated from leaves of Pisum sativum L. (cv Marzia) were compared with those of the enzyme partially purified (316-fold) from shoots of seedlings after 3 weeks of cultivation.Both preparations showed a pH optimum at pH 8.3 and had the same affinity to ornithine (K(m) = 1.2 millimolar) as well as to carbamoyl phosphate (K(m) = 0.2 millimolar). The approximate molecular weight determined by gel sieving was 77,600.A desalted ammonium sulfate precipitate from 14-day seedlings (inclusive roots and senescing cotyledons) was applied on a column of anion exchanger. The elution pattern showed one peak of ornithine carbamoyl-transferase activity. This elution pattern was the same as observed for the enzyme from chloroplasts.The results suggest the presence of one form of ornithine carbamoyl-transferase in pea seedlings.