Glycosidases induced in Aspergillus tamarii Secreted at - D - galactosidase andf / - D - mannanase

An a-D-galactosidase (EC 3.2.1.22) and a fl-D-mannanase (EC 3.2.1.78), which were secreted into the growth medium when Aspergillus tamarii was cultivated in the presence of galactomannan, were purified by a procedure including chromatography on hydroxyapatite and DEAE-cellulose columns. Each of these enzymes showed a single protein band, corresponding to their respective activities, on polyacrylamidegel electrophoresis. Both enzymes were shown to be glycoproteins containing Nacetylglucosamine, mannose and galactose, with molar proportions of 1: 6:1.5 for aD-galactosidase and 1:13 :8 for 3-D-mannanase. Mr values as determined by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate and by the electrophoretic method of Hedrick & Smith [(1968) Arch. Biochem. Biophys. 126, 155164] were 56000 and 53000 respectively. The ct-D-galactosidase differed markedly from the mycelial forms I and II studied in the preceding paper [Civas, Eberhard, Le Dizet & Petek (1984) Biochem. J. 219, 849-855] with regard to both its kinetic and structural properties.