Alpha-D-Mannosidase from Capsicum Annuum

Alpha-D-Mannosidase (EC 3.2.1.24), a glycosidase showing a consistent increase in activity with the
progress in softening in Capsicum annuum, was purified to electrophoretic homogeneity by fractionation with
ammonium sulphate followed by gel filtration on Sephadex G-100, ion-exchange chromatography on DEAE
Sephadex A-50 and HPLC gel filtration on GF 250. The purified enzyme had a native and a SDS M, of 43 000 and
23 000, respectively. The optimal pH was 5.7 and the optimal temperature was 50”. The enzyme was thermally
stable up to 60” for 15 min. The K, for p-nitrophenyl alpha-D-mannopyranoside was 0.7 mM. The enzyme activity was
inhibited nearly 95% by Fe’+ and Cu” at 0.1 mM. The preparation was free of other glycosidases. Antibodies
were raised against the purified enzyme for further studies on the physiological function of a-D-mannosidase in
fruit systems. This is the first report on purification to homogeneity and characterization of alpha-D-mannosidase from fruit systems.