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Titolo:
THE ROLE OF THROMBINS TYR-PRO-PRO-TRP MOTIF IN THE INTERACTION WITH FIBRINOGEN, THROMBOMODULIN, PROTEIN-C, ANTITHROMBIN-III, AND THE KUNITZINHIBITORS
Autore:
LEBONNIEC BF; GUINTO ER; MACGILLIVRAY RTA; STONE SR; ESMON CT;
Indirizzi:
UNIV CAMBRIDGE,CTR MRC,DEPT HAEMATOL,HILLS RD CAMBRIDGE CB2 2QH ENGLAND OKLAHOMA MED RES FDN,CARDIOVASC BIOL RES PROGRAM OKLAHOMA CITY OK 73104 UNIV BRITISH COLUMBIA,DEPT BIOCHEM VANCOUVER V6T 1W5 BC CANADA UNIV OKLAHOMA HLTH SCI CTR,HLTH SCI CTR,DEPT PATHOL OKLAHOMA CITY OK 73103 HOWARD HUGHES MED INST OKLAHOMA CITY OK 73103 UNIV OKLAHOMA HLTH SCI CTR,HLTH SCI CTR,DEPT BIOCHEM OKLAHOMA CITY OK73103
Titolo Testata:
The Journal of biological chemistry
fascicolo: 25, volume: 268, anno: 1993,
pagine: 19055 - 19061
SICI:
0021-9258(1993)268:25<19055:TROTTM>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
HUMAN ALPHA-THROMBIN; COMPLEMENTARY DEOXYRIBONUCLEIC-ACID; BLOOD-COAGULATION; HIRUDIN COMPLEX; CRYSTAL-STRUCTURE; FACTOR-XIII; ARG CHLOROMETHYLKETONE; SEQUENCE-ANALYSIS; HEPARIN COFACTOR; RESIDUES 7-16;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
67
Recensione:
Indirizzi per estratti:
Citazione:
B.F. Lebonniec et al., "THE ROLE OF THROMBINS TYR-PRO-PRO-TRP MOTIF IN THE INTERACTION WITH FIBRINOGEN, THROMBOMODULIN, PROTEIN-C, ANTITHROMBIN-III, AND THE KUNITZINHIBITORS", The Journal of biological chemistry, 268(25), 1993, pp. 19055-19061

Abstract

When amino acids Pro60B, Pro60C, and Trp60D are deleted from thrombin, the resulting mutant (des-PPW) exhibits (compared to the wild-type enzyme): a similar second order rate constant of inhibition (k(on)) fordiisopropyl fluorophosphate, and a comparable inhibition constant (K(i)) for benzamidine, suggesting that the charge stabilizing system andthe primary binding pocket are little altered, if at all, by the mutation. As predicted from the x-ray structure, des-PPW is remarkably sensitive to the bovine pancreatic trypsin inhibitor, with a K(i) over 3 x 10(3) times tighter relative to thrombin, but des-PPW is also markedly less susceptible to inactivation by antithrombin III, with a k(on) that is over 100-fold lower. The catalytic constant (k(cat)) for most p-nitroanilide substrates tested is preserved or even increased, but the Michaelis constant (K(m)) increases. In contrast, the K(m) for the fibrinogen A alpha-chain is essentially unchanged, whereas k(cat) decreases almost-equal-to 50-fold. Unlike thrombin, the rate of fibrinopeptide B release becomes, following a lag phase, comparable to that of fibrinopeptide A. Inasmuch as des-PPW cleaves an additional peptide bond in the bovine fibrin alpha-chain, it remains a highly specific serine protease, which releases a single peptide from denatured casein (versus two with thrombin). Protein C activation by des-PPW is almost-equal-to 30 times slower than by thrombin in the absence, as well as in the presence, of calcium and thrombomodulin. Although this study confirms that the B-insertion restricts access to the active site cleft, it also suggests that other motifs and/or discrete amino acids are mainly responsible for the narrow specificity of thrombin.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/07/20 alle ore 22:37:01