Enzymic and physicochemical properties of an exo-(1→3)-β-d-glucanase from Rhizoctonia solani

✍ Scribed by Naohito Ohno; Isao Nono; Toshiro Yadomae

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 588 KB
• Volume: 194
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(89)85024-4

✦ Synopsis

An exo-(143)/3-D-glucanase, isolated from a commercial lytic enzyme preparation "kitalase", had mol. wt. 74,000, isoelectric point pH 8.1, optimum pH 5.6, optimum temperature 53", pH stability 5.0-8.0, and temperature stability up to 65". The enzyme contained 703 amino acids, including 10 Cys, 7 Trp, 11 His, 83 Asp (Asn), and 51 Glu (Gln). The activity was inhibited on modification of the tryptophan, histidine, or carboxyl residues. Oxidation of Trp was inhibited by the addition of substrate. The enzyme released only glucose from a (1+3)-P-D-glucan, glucose and gentiobiose from a 6-branched (l-+3)-P-D-glucan, and had no effect on gentiobiose and methyl (Y-and jI-D-glucopyranosides.

For the series of laminarioligosaccharides G3-G7, the relative velocities of reaction compared to that of laminarin were G7:G6:G5:G4:G3 = 77:65:54:34:3. The enzyme acted on the glucan that had the reducing end modified but not that with the non-reducing end modified. The glucose residues liberated were (Y. The enzyme is suitable for use in the structural characterization of (1-3)~j?-D-glucans.