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Titolo:
Roles of His-79 and Tyr-180 of D-xylose/dihydrodiol dehydrogenase in catalytic function
Autore:
Asada, Y; Aoki, S; Ishikura, S; Usami, N; Hara, A;
Indirizzi:
Gifu Pharmaceut Univ, Biochem Lab, Gifu, Japan Gifu Pharmaceut Univ GifuJapan armaceut Univ, Biochem Lab, Gifu, Japan
Titolo Testata:
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
fascicolo: 2, volume: 278, anno: 2000,
pagine: 333 - 337
SICI:
0006-291X(20001119)278:2<333:ROHATO>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIMERIC DIHYDRODIOL DEHYDROGENASE; GLUCOSE-FRUCTOSE OXIDOREDUCTASE; 3-ALPHA-HYDROXYSTEROID DEHYDROGENASE; ZYMOMONAS-MOBILIS; PIG-LIVER; BINDING; PURIFICATION; REDUCTASES; CLONING; PROTEIN;
Keywords:
dihydrodiol dehydrogenase; glucose-fructose oxidoreductase; catalytic residue; coenzyme binding; ionic strength; fluorescence energy transfer; protein family;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
23
Recensione:
Indirizzi per estratti:
Indirizzo: Hara, A Gifu Pharmaceut Univ, Biochem Lab, 5-6-1 Mitahora Higashi, Gifu, Japan Gifu Pharmaceut Univ 5-6-1 Mitahora Higashi Gifu Japan fu, Japan
Citazione:
Y. Asada et al., "Roles of His-79 and Tyr-180 of D-xylose/dihydrodiol dehydrogenase in catalytic function", BIOC BIOP R, 278(2), 2000, pp. 333-337

Abstract

Mammalian dimeric dihydrodiol dehydrogenase is identical with D-xylose dehydrogenase and belongs to a protein family with prokaryotic proteins including glucose-fructose oxidoreductase. Of the conserved residues in this family, either His-79 or Tyr-180 of D-xylose/dihydrodiol dehydrogenase has beenproposed to be involved in the catalytic function. Site-directed mutagenesis was used to examine the roles of the two residues of the monkey enzyme. A mutant, Y180F, was almost inactive, but, similarly to the wildtype enzyme, exhibited high affinity for NADP(H) and fluorescence energy transfer uponbinding of NADPH. The H79Q mutation had kinetically largest effects on K-d(>7-fold increase) and K-m (>25-fold increase) for NADP(H), and eliminatedthe fluorescence energy transfer. Interestingly, the dehydrogenase activity of this mutant was potently inhibited with a 190-fold increase in the K-mfor NADP(+) by high ionic strength, which activated the activity of the wild-type enzyme. These results suggest a critical role of Tyr-180 in the catalytic function of this class of enzymes, in addition to functions of His-79 in the coenzyme binding and chemical steps of the reaction. (C) 2000 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/05/20 alle ore 14:54:18