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Titolo:
SUBSTRATE-SPECIFICITY OF ACETYLXYLAN ESTERASE FROM SCHIZOPHYLLUM-COMMUNE - MODE OF ACTION ON ACETYLATED CARBOHYDRATES
Autore:
BIELY P; COTE GL; KREMNICKY L; WEISLEDER D; GREENE RV;
Indirizzi:
SLOVAK ACAD SCI,INST CHEM,DUBRAVSKA CESTA 9 BRATISLAVA 84238 SLOVAKIA USDA ARS,NATL CTR AGR UTILIZAT RES,BIOPOLYMER RES UNIT PEORIA IL 61604 USDA ARS,NATL CTR AGR UTILIZAT RES,ANALYT CHEM SERV PEORIA IL 61604
Titolo Testata:
Biochimica et biophysica acta. Protein structure and molecular enzymology
fascicolo: 2, volume: 1298, anno: 1996,
pagine: 209 - 222
SICI:
0167-4838(1996)1298:2<209:SOAEFS>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
LIPASE-CATALYZED HYDROLYSIS; TRICHODERMA-REESEI; DEACETYLATION; XYLAN; PURIFICATION; QUANTITATION; DEACYLATION; PROTEINS; SYSTEMS; SUGARS;
Keywords:
ACETYLXYLAN ESTERASE; SUBSTRATE SPECIFICITY; ACETYLATED METHYL GLYCOSIDES; MODE OF ACTION; (S-COMMUNE);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
46
Recensione:
Indirizzi per estratti:
Citazione:
P. Biely et al., "SUBSTRATE-SPECIFICITY OF ACETYLXYLAN ESTERASE FROM SCHIZOPHYLLUM-COMMUNE - MODE OF ACTION ON ACETYLATED CARBOHYDRATES", Biochimica et biophysica acta. Protein structure and molecular enzymology, 1298(2), 1996, pp. 209-222

Abstract

Substrate specificity of a purified acetylxylan esterase from Schizophyllum commune was investigated on a variety of methyl per-O-acetyl glycopyranosides, methyl di-O-acetyl-beta-D-xylopyranosides and acetylated polysaccharides. The enzyme preferentially deacetylated the 3-position of methyl 2,3,4-tri-O-acetyl-beta-D-xylopyranoside and 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside. Removal of the 3-acetyl group fromthe xylopyranoside was accompanied by a slower deacetylation at positions 2 and 4. A similarly slower, accompanying deacetylation occurred primarily at position 2 with the glucopyranoside. Such specificity corresponds well to the expected function of the esterase in acetylxylan degradation. Of the three possible diacetates of methyl beta-D-xylopyranoside, the 3,4-diacetate was found to be the most rapidly deacetylated. Unexpectedly, products of its deacetylation were a mixture of 2- and 4-monoacetate. The formation of the methyl 2-O-acetyl-beta-D-xylopyranoside involved an enzyme-mediated acetyl group transfer because therate of the enzyme-catalyzed reaction exceeded the rate of spontaneous migration of acetyl groups. This is the likely mechanism for acetyl removal from position 2 in the native substrate. The enzyme exhibited the highest regioselectivity with methyl 2,3,4,6-tetra-O-acetyl-beta-D-mannopyranoside. An 80% conversion of this substrate to methyl 4,6-di-O-acetyl-beta-D-mannopyranoside, a new mannose derivative, was achieved. In contrast to the majority of lipases and esterases exploited forregioselective deacetylation, the S. commune acetylxylan esterase didnot attack the C-6 acetyl linkages in methyl hexopyranosides when other acetyl groups were available.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/07/20 alle ore 10:23:26