Partial purification and biochemical characterization of a soluble alpha-glucosidase II-like activity from Candida...

A soluble alpha-glucosidase was partially purified from Candida albicans cells by a three-step procedure consisting of size-exclusion, ion-exchange and adsorption chromatographies. After the last step, enzyme was enriched about 8.7-fold with a yield of 13% over the starting material and analysis of the purified preparation revealed two major polypeptides of 36 and 47 kDa. The latter was responsible for enzyme activity as visualized with a fluorescent substrate. Nigerose, an alpha-1,3-linked glucose disaccharide, was preferentially hydrolyzed by the purified enzyme over other glucosedisaccharides bearing distinct alpha-linkages. The purified alpha-glucosidase also converted the GlcMan9GlcNAc2 oligosaccharide into the Man9GlcNAc2 product in a time-dependent manner. These and other determined properties are consistent with a type GII alpha-glucosidase probably involved in N-glycan processing.