Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
DETERMINANTS OF PERFORMANCE IN THE ISOCITRATE DEHYDROGENASE OF ESCHERICHIA-COLI
Autore:
DEAN AM; SHIAU AK; KOSHLAND DE;
Indirizzi:
UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL BERKELEY CA 94720 UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL BERKELEY CA 94720 CHICAGO MED SCH,DEPT BIOL CHEM N CHICAGO IL 60064
Titolo Testata:
Protein science
fascicolo: 2, volume: 5, anno: 1996,
pagine: 341 - 347
SICI:
0961-8368(1996)5:2<341:DOPITI>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTIVE-SITE; MALIC-ACID; PHOSPHORYLATION; MECHANISM; ENZYME; PHOSPHATE;
Keywords:
ENZYME PERFORMANCE; ISOCITRATE DEHYDROGENASE; STABILIZATION OF MICHAELIS COMPLEX;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
22
Recensione:
Indirizzi per estratti:
Citazione:
A.M. Dean et al., "DETERMINANTS OF PERFORMANCE IN THE ISOCITRATE DEHYDROGENASE OF ESCHERICHIA-COLI", Protein science, 5(2), 1996, pp. 341-347

Abstract

The substrate specificity of the NADP-dependent isocitrate dehydrogenase oi Escherichia coli was investigated by combining site-directed mutagenesis and utilization of alternative substrates. A comparison of the kinetics of the wild-type enzyme with 2R-malate reveals that the gamma-carboxylate of 2R,3S-isocitrate contributes a factor of 12,000,000to enzyme performance. Analysis of kinetic data compiled for 10 enzymes and nine different substrates reveals that a factor of 1,650 can beascribed to the hydrogen bond formed between S113 and the gamma-carboxylate of bound isocitrate, a factor of 150 to the negative charge of the gamma-carboxylate, and a factor of 50 for the gamma-methyl. These results are entirely consistent with X-ray structures of Michaelis complexes that show a hydrogen bond positions the gamma-carboxylate of isocitrate so that a salt bridge can form to the nicotinamide ring of NADP.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 18/09/20 alle ore 20:00:51