Purification and Properties of the Diamine Oxidase from Vicia faba Leaves

Diamine oxidase (EC 1.4.3.6 EC] ) from the leaves of Vicia faba waspurified to homogeneity by polyacrylamide gel electrophoresis.The molecular weight estimated by Sephadex G-200 gel filtrationwas about 126,000. Sodium dodecyl sulfate gel electrophoresisgave a single band at the molecular weight of 74,000. The isoelectricpoint was at pH 7.2. The enzyme contained two copper atoms permole of enzyme. Inhibition with phenylhydrazine showed thatthe Vicia enzyme contains one mole of the carbonyl group permole of the enzyme. The amino acid composition of the enzymealso is described. (Received February 23, 1981; Accepted April 7, 1981)