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Titolo:
Inhibition of the aminopeptidase from Aeromonas proteolytica by aliphatic alcohols. Characterization of the hydrophobic substrate recognition site
Autore:
Ustynyuk, L; Bennett, B; Edwards, T; Holz, RC;
Indirizzi:
Utah State Univ, Dept Chem & Biochem, Logan, UT 84322 USA Utah State UnivLogan UT USA 84322 pt Chem & Biochem, Logan, UT 84322 USA
Titolo Testata:
BIOCHEMISTRY
fascicolo: 35, volume: 38, anno: 1999,
pagine: 11433 - 11439
SICI:
0006-2960(19990831)38:35<11433:IOTAFA>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
STREPTOMYCES-GRISEUS AMINOPEPTIDASE; TRANSITION-STATE-ANALOG; LENS LEUCINE AMINOPEPTIDASE; L-LEUCINEPHOSPHONIC ACID; METHIONINE AMINOPEPTIDASE; BOVINE LENS; CATALYTIC MECHANISM; ANGSTROM RESOLUTION; PEPTIDE HYDROLYSIS; CRYSTAL-STRUCTURE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Holz, RC Utah State Univ, Dept Chem & Biochem, Logan, UT 84322 USA Utah State Univ Logan UT USA 84322 Biochem, Logan, UT 84322 USA
Citazione:
L. Ustynyuk et al., "Inhibition of the aminopeptidase from Aeromonas proteolytica by aliphatic alcohols. Characterization of the hydrophobic substrate recognition site", BIOCHEM, 38(35), 1999, pp. 11433-11439

Abstract

Seven aliphatic and two aromatic alcohols were tested as reporters of the substrate selectivity of the aminopeptidase from Aeromonas proteolytica (AAP). This series of alcohols was chosen to systematically probe the effect of carbon chain length, steric bulk, and inhibitor shape on the inhibition of AAP. Initially, however, the question of whether AAP is denatured in the presence of aliphatic alcohols was addressed. On the basis of circular dichroism (CD), electronic absorption, and fluorescence spectra, the secondary structure of AAP, with and without added aliphatic alcohols, was unchanged. These data clearly indicate that AAP is not denatured in aliphatic alcohols, even up to concentrations of 20% (v/v). All of the alcohols studied werecompetitive inhibitors of AAP with K-i values between 860 and 0.98 mM, Theclear trend in the data was that as the carbon chain length increases fromone to four, the K-i values increase. Branching of the carbon chains also increases the K-i values, but large bulky groups, such as that found in tert-butyl alcohol, do not inhibit AAP as well as leucine analogues, such as 3-methyl-1-butanol. The competitive nature of the inhibition indicates that the substrate and each alcohol studied are mutually exclusive due to binding at the same site on the enzyme. On the basis of EPR and electronic absorption data for Co(II)-substituted AAP, none of the alcohols studied binds tothe dinuclear metallo-active site of AAP. Thus, reaction of the inhibitoryalcohols with the catalytic metal ions cannot constitute the mechanism of inhibition, Combination of these data suggests that each of these inhibitors bind only to the hydrophobic pocket of AAP and, consequently, block the binding of substrate. Thus, the first step in peptide hydrolysis is the recognition of the N-terminal amino acid side chain by the hydrophobic pocket adjacent to the dinuclear active site of AAP.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 14:13:05