Title

Extracellular Alpha-Galactosidase (Ec 3.2.1.22) From Aspergillus-Ficuum Nrrl-3135 Purification And Characterization

Title - Alternative

Prep. Biochem.

Keywords

POLYACRYLAMIDE-GEL ELECTROPHORESIS; OPTIMUM ACID-PHOSPHATASE; SOYBEAN; MILK; ROOT-TIPS; GLYCOSIDASES; ISOENZYMES; SEQUENCE; PHYTASE; NIGER; Biochemistry & Molecular Biology

Abstract

Extracellular alpha-galactosidase, a glycoprotein from the extracellular culture fluid of Aspergillus ficuum grown on glucose and raffinose in a batch culture system, was purified to homogeneity in five steps by ion exchange and hydrophobic interaction chromatography. The molecular mass of the enzyme was 70.8 Kd by SDS polyacrylamide gel electrophoresis and 74.1 Kd by gel permeation HPLC. On the basis of a molecular mass of 70.7 Kd, the molar extinction coefficient of the enzyme at 279 nm was estimated to be 6.1 X10(4) M-1 cm-1. The purified enzyme was remarkably stable at 0-degrees-C. It had a broad temperature optimum and maximum catalytic activity was at 60-degrees-C. It retained 33% of its activity after 10 min. at 65-degrees-C. It had a pH optimum of 6.0. It retained 62% of its activity after 12 hours at pH 2.3. The K(ms) for p-nitrophenyl-alpha-D-galactopyranoside, o-nitrophenyl-alpha-D-galactopyranoside and m-nitrophenyl-alpha-D-galactopyranoside are: 1462, 839 and 718-mu-M. The enzyme was competitively inhibited by mercury (19.8-mu-M), silver (21.5-mu-M), copper (0.48 mM), zinc (0.11 mM), galactose (64.0 mM) and fructose (60.3 mM). It was inhibited non-competitively by glucose (83.2 mM) and uncompetitively by mannose (6.7 mM).

Publication Title

Preparative Biochemistry

Volume

20

Issue/Number

3-4

Publication Date

1-1-1990

Document Type

Article

Language

English

First Page

263

Last Page

296

WOS Identifier

WOS:A1990FG18500006

ISSN

0032-7484

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