Properties of Ornithine Carbamoyltransferase from Pisum sativum L.

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.