Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Roles of Hs205, His296, His303 and Asp259 in catalysis by NAD(+)-specific D-lactate dehydrogenase
Autore:
Kochhar, S; Lamzin, VS; Razeto, A; Delley, M; Hottinger, H; Germond, JE;
Indirizzi:
Nestle Res Ctr, CH-1000 Lausanne 26, Switzerland Nestle Res Ctr LausanneSwitzerland 26 CH-1000 Lausanne 26, Switzerland DESY, European Mol Biol Lab, D-2000 Hamburg, Germany DESY Hamburg Germany D-2000 ropean Mol Biol Lab, D-2000 Hamburg, Germany
Titolo Testata:
EUROPEAN JOURNAL OF BIOCHEMISTRY
fascicolo: 6, volume: 267, anno: 2000,
pagine: 1633 - 1639
SICI:
0014-2956(200003)267:6<1633:ROHHHA>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
2-HYDROXY ACID DEHYDROGENASES; DELBRUECKII SUBSP BULGARICUS; LIGAND-BINDING SITES; ESCHERICHIA-COLI; CRYSTAL-STRUCTURE; TERNARY COMPLEX; BACILLUS-STEAROTHERMOPHILUS; LACTOBACILLUS-PLANTARUM; ACTIVE-SITE; RESOLUTION;
Keywords:
D-2-hydroxy acid dehydrogenases; D-lactate dehydrogenase; Lactobacillus bulgaricus; site-directed mutagenesis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Kochhar, S Nestle Res Ctr, Vers Chez Blanc,POB 44, CH-1000 Lausanne 26, Switzerland Nestle Res Ctr Vers Chez Blanc,POB 44 Lausanne Switzerland 26
Citazione:
S. Kochhar et al., "Roles of Hs205, His296, His303 and Asp259 in catalysis by NAD(+)-specific D-lactate dehydrogenase", EUR J BIOCH, 267(6), 2000, pp. 1633-1639

Abstract

The role of three histidine residues (His205, His296 and His303) and Asp259, important for the catalysis of NAD(+)-specific D-lactate dehydrogenase, was investigated using site-directed mutagenesis. None of these residues ispresumed to be involved in coenzyme binding because K-m for NADH remained essentially unchanged for all the mutant enzymes. Replacement of His205 with lysine resulted in a 125-fold reduction in k(cat) and a slight lowering of the K-m value for pyruvate. D259N mutant showed a 56-fold reduction in k(cat) and a fivefold lowering of K-m. The enzymatic activity profile shiftedtowards acidic pH by approximate to 2 units. The H303K mutation produced no significant change in k(cat) values, although K-m for pyruvate increased fourfold. Substitution of His296 with lysine produced no significant changein k(cat) values or in K-m for substrate. The results obtained suggest that His205 and Asp259 play an important role in catalysis, whereas His303 does not. This corroborates structural information available for some members of the d-specific dehydrogenases family. The catalytic His296, proposed from structural studies to be the active site acid/base catalyst, is not invariant. Its function can be accomplished by lysine and this has significant implications for the enzymatic mechanism.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/12/20 alle ore 15:20:42