Purification of guanosine 5′-diphosphate d-mannose oxidoreductase from Phaseolus vulgaris

Abstract

An enzyme characterized as GDP- d-mannose oxidoreductase has been extracted from seedlings of Phaseolus vulgaris and purified to apparent homogeneity by (NH 4) 2SO 4 precipitation and chromatography on columns of DEAE-cellulose, Sephadex G-100 and hydroxylapatite. Only one protein band could be detected upon sedimentation velocity ultracentrifugation or disc gel electrophoresis of the enzyme preparation. The molecular weight of the enzyme was estimated at 120 000 by sedimentation equilibrium analysis. No requirement for a pyridine nucleotide or any other cofactor could be demonstrated in the reaction catalyzed by the purified enzyme.