PURIFICATIONAND PROPERTIES OF AN a-GALACTOSIDASE FROM Lenzites elegans

SAMPIETRO, D. A.; SGARIGLIA, M. A.; SOBERÓN, J.R.; VATUONE, M. A.

Tafi del Valle

Congreso; XXVIII Annual scientific meeting of the Tucuman biology association; 2011

Tucuman biology association

Introduction: White rot fungi degrade hetero-1,4-b-D-xylans, hetero 1,4-b-D -mannans, galacto-glucomannans and glucomannans. Objectives: Purification of an a-galactosidase from L. elegans, and study of its physicochemical and kinetic properties. Materials and methods: Lenzites elegans isolated from decaying wood was used. a-Galactosidase was isolated and purified from the cultura medium. Results and discussion: The Mr of the enzyme was 158 kDa with two subunits (Mr =61 kDa). The optimal temperature was in the 60-80°C range. Optimal pH was 4.5 and was stable from pH 3 to 7.5 after preincubation at 60°C for 2 h. It is a glycoprotein active against a-D-galactopyranosides. Galactose is a non-competitive inhibitor (Ki = 22 mM vs. p-nitrophenyl-a-D-galactoside and 12mM vs. a-D-melibiose as substrates) . Glucose was a competitive inhibitor (Ki = 10mM). Hg2+, Ag!' and p-chloromercuribenzoate were inhibitors, suggesting the presence of-SH groups in the active site . The N-terminal end (SPDTIVLDGTNFALN) suggests that it belongs to the glycosyl hydrolase family 36.Conclusions: This fungus may become a useful source of a-galactosidase production for industrial use.