Purification and characterization of ACC oxidase from Artocarpus altilis

1-Aminocyclopropane-1-carboxylic acid (ACC) oxidase was purified to homogeneity from breadfruit (Artocarpus altilis) by a six-step chromatography procedure to yield an 87-fold increase in purification with a recovery of 9.5%. SDS-PAGE revealed that the purified enzyme had a molecular mass of 42.3 kDa and a Km of 28.2 muM. The enzyme showed marked inhibition by cobalt sulphate, sodium metabisulphite, sodium dithionite, n-propyl gallate, zinc sulphate and hydrogen peroxide. Dithiothreitol (DTT) enhanced enzyme activity when it was included in the assay medium. Optimum activity of ACC oxidase was obtained at a pH of 7.2 at 28 degreesC. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.