Structure and properties of a Cephalosporium acremonium alpha-galactosidase.

The amino acid and sugar composition of the enzyme protein, the effect of urea, sodium dodecyl sulphate and Concanavalin A on the purified alpha-galactosidase (EC 3.2.1.22) from the mold Cephalosporium acremonium has been studied. The results obtained by gas liquid chromatography indicated the presence of N-acetylglucosamine, mannose, galactose and N-acetylneuramic acid in the molar proportions 2:7:3:11. The presence of two types of Asn-linked oligosaccharide structures in the enzyme molecule is assumed. The alpha-galactosidase liberates alpha(1-3), alpha(1-4) and alpha(1-6)-linked D-galactose units from various synthetic and natural substrates which have been tested. The effects of pH, substrate concentration and temperature on the catalytic activity of the enzyme are described. The purified alpha-galactosidase also exhibited a lectin activity with an affinity towards glucose, and to some extent mannose.