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Titolo:
Purification and substrate specificity of honeybee, Apis mellifera L., alpha-glucosidase III
Autore:
Nishimoto, M; Kubota, M; Tsuji, M; Mori, H; Kimura, A; Matsui, H; Chiba, S;
Indirizzi:
Hokkaido Univ, Grad Sch Agr, Div Appl Biosci, Sapporo, Hokkaido 0608589, Japan Hokkaido Univ Sapporo Hokkaido Japan 0608589 oro, Hokkaido 0608589, Japan
Titolo Testata:
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY
fascicolo: 7, volume: 65, anno: 2001,
pagine: 1610 - 1616
SICI:
0916-8451(200107)65:7<1610:PASSOH>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
SUBSITE AFFINITIES; ANOMERIC FORMS; CARBOHYDRASES; GLUCOAMYLASE; PRODUCTS;
Keywords:
honeybee alpha-glucosidase; substrate specificity; allosteric behavior; subsite affinity;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
18
Recensione:
Indirizzi per estratti:
Indirizzo: Chiba, S Hokkaido Univ, Grad Sch Agr, Div Appl Biosci, Sapporo, Hokkaido 0608589, Japan Hokkaido Univ Sapporo Hokkaido Japan 0608589 aido 0608589, Japan
Citazione:
M. Nishimoto et al., "Purification and substrate specificity of honeybee, Apis mellifera L., alpha-glucosidase III", BIOS BIOT B, 65(7), 2001, pp. 1610-1616

Abstract

alpha -Glucosidase III, which was different in substrate specificity from honeybee alpha -glucosidases I and II, was purified as an electrophoretically homogeneous protein from honeybees, by salting-out chromatography, DEAE-cellulose, DEAE-Sepharose CL-6B, Bio-Gel P-150, and CM-Toyopearl 650M column chromatographies. The enzyme preparation was confirmed to be a monomeric protein and a glycoprotein containing about 7.4% of carbohydrate. The molecular weight was estimated to approximately 68,000, and the optimum pH was 5.5. The substrate specificity of alpha -glucosidase III was kinetically investigated. The enzyme did not show unusual kinetics, such as the allostericbehaviors observed in alpha -glucosidases I and II, which are monomeric proteins. The enzyme was characterized by the ability to rapidly hydrolyze sucrose, phenyl alpha -glucoside, maltose, and maltotriose, and by extremely high K-m for substrates, compared with those of alpha -glucosidases I and II. Especially, maltotriose was hydrolyzed over 3 times as rapidly as maltose. However, maltooligosaccharides of four or more in the degree of polymerization were slowly degraded. The relative rates of the k(o) values for maltose, sucrose, p-nitrophenyl alpha -glucoside and maltotriose were estimatedto be 100, 527, 281 and 364, and the K-m values for these substrates, 11, 30, 13, and 10 mm, respectively. The subsite affinities (A(i)'s) in the active site were tentatively evaluated from the rate parameters for maltooligosaccharides. In this enzyme, it was peculiar that the A(i) value at subsite3 was larger than that of subsite 1.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 13/07/20 alle ore 07:20:59