Section 7
Chapter 6,228

Purification and enzymatic properties of alpha galactosidase ec from pycnoporus cinnabarinus

Ohtakara, A.; Mitsutomi, M.; Uchida, Y.

Agricultural and Biological Chemistry 48(5): 1319-1328


ISSN/ISBN: 0002-1369
Accession: 006227998

.alpha.-Galactosidase (EC from P. cinnabarinus was purified by precipitations with ammonium sulfate, column chromatographies on DEAE-Sephadex A-50, Sephadex G-100, CM-Sephadex C-50, and SP-Sephadex C-50, and isoelectric focusing. The purified enzyme was homogeneous on polyacrylamide disc gel electrophoresis, and the molecular weight was estimated to be about 210,000 by gel filtration on Sephacryl S-200 and about 52,000 by sodium dodecyl sulfate gel electrophoresis. The enzyme exhibited the optimum pH at 5.0 and was stable at pH 3-9. The optimum temperature of the enzyme was 75.degree. C. The enzyme was thermostable at pH 5.0 and completely lost its activity after heating at 90.degree. C or at pH 3.5. The Km were 0.31 mM for p-nitrophenyl .alpha.-D-galactoside, 0.80 mM for melibiose, 2.16 mM for raffinose, and 1.15 mM for stachyose. The .alpha.-galactosidase activity was strongly inhibited by Ag+, Hg2+, p-chloromercuribenzoate, galactose and melibiose. The enzyme also seemed to catalyze a glycosyltransfer reaction.

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