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Titolo:
TRANSITION-STATE STRUCTURE OF SALMONELLA-TYPHIMURIUM OROTATE PHOSPHORIBOSYLTRANSFERASE
Autore:
TAO W; GRUBMEYER C; BLANCHARD JS;
Indirizzi:
YESHIVA UNIV ALBERT EINSTEIN COLL MED,DEPT BIOCHEM,1300 MORRIS PK AVEBRONX NY 10461 YESHIVA UNIV ALBERT EINSTEIN COLL MED,DEPT BIOCHEM BRONX NY 10461 TEMPLE UNIV,SCH MED,DEPT BIOCHEM PHILADELPHIA PA 19140
Titolo Testata:
Biochemistry
fascicolo: 1, volume: 35, anno: 1996,
pagine: 14 - 21
SICI:
0006-2960(1996)35:1<14:TSOSOP>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
KINETIC MECHANISM; AMP NUCLEOSIDASE; HYDROLYSIS; ENZYME; INHIBITORS; SYNTHETASE; PURINE; BOND; ACID;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
36
Recensione:
Indirizzi per estratti:
Citazione:
W. Tao et al., "TRANSITION-STATE STRUCTURE OF SALMONELLA-TYPHIMURIUM OROTATE PHOSPHORIBOSYLTRANSFERASE", Biochemistry, 35(1), 1996, pp. 14-21

Abstract

Orotate phosphoribosyltransferase (OPRTase) catalyzes the magnesium-dependent conversion of alpha-D-phosphoribosylpyrophosphate (PRPP) and orotate to orotidine 5'-monophosphate (OMP) and pyrophosphate. We havedetermined kinetic isotope effects on the reaction of OMP with pyrophosphate and with the pyrophosphate analog phosphonoacetic acid. In thelatter case, full expression of the kinetic isotope effects allowed us to calculate the structure of the transition state for the pyrophosphorylytic reaction. The transition state resembles a classical oxocarbonium ion. Using the recently reported three-dimensional structures ofthe OPRTase-OMP (Scapin et al., 1994) and the OPRTase-PRPP complexes (Scapin et al., 1995a), we have modeled the calculated transition state structure into the active site of OPRTase. We propose a detailed chemical mechanism which is consistent with these results.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 18/09/20 alle ore 11:09:37