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Titolo:
METABOLISM OF ASPARTAME BY HUMAN AND PIG INTESTINAL MICROVILLAR PEPTIDASES
Autore:
HOOPER NM; HESP RJ; TIEKU S;
Indirizzi:
UNIV LEEDS,DEPT BIOCHEM & MOLEC BIOL LEEDS LS2 9JT W YORKSHIRE ENGLAND
Titolo Testata:
Biochemical journal
, volume: 298, anno: 1994,
parte:, 3
pagine: 635 - 639
SICI:
0264-6021(1994)298:<635:MOABHA>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
RENAL DIPEPTIDASE; CONVERTING ENZYME; KIDNEY; AMINOPEPTIDASE; HYDROLYSIS; MEMBRANE; PURIFICATION; INHIBITORS; PROTEINS; PRODUCT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
21
Recensione:
Indirizzi per estratti:
Citazione:
N.M. Hooper et al., "METABOLISM OF ASPARTAME BY HUMAN AND PIG INTESTINAL MICROVILLAR PEPTIDASES", Biochemical journal, 298, 1994, pp. 635-639

Abstract

The artificial sweetener aspartame (N-L-alpha-aspartyl-L-phenylalanine-1-methyl ester; Nutrasweet), its decomposition product alphaAsp-Phe and the related peptide alphaAsp-PheNH2 were rapidly hydrolysed by microvillar membranes prepared from human duodenum, jejunum and ileum, and from pig duodenum and kidney. The metabolism of aspartame by the human and pig intestinal microvillar membrane preparations was inhibited significantly (> 78%) by amastatin or 1,10-phenanthroline, and partially (> 38%) by actinonin or bestatin, and was activated 2.9-4.5-fold byCaCl2. The inhibition by amastatin and 1,10-phenanthroline, and the activation by CaCl2 are characteristic of the cell-surface ectoenzyme aminopeptidase A (EC 3.4.11.7) and a purified preparation of this enzyme hydrolysed aspartame with a K(m) of 0.25 mM and a V(max) of 126 mumol/min per mg. A purified preparation of aminopeptidase W (EC 3.4.11.16) also hydrolysed aspartame but with a K(m) of 4.96 mM and a V(max) of110 mumol/min per mg. However, rentiapril, an inhibitor of aminopeptidase W, caused only slight inhibition (maximally 19%) of the hydrolysis of aspartame by the microvillar membrane preparations. Similar patterns of inhibition and kinetic parameters were observed for alphaAsp-Phe and alphaAsp-PheNH2. Two other decomposition products of aspartame, betaAsp-PheMe and cyclo-Asp-Phe, were essentially resistant to hydrolysis by both the human and pig intestinal microvillar membrane preparations and the purified preparations of aminopeptidases A and W. Although the relatively selective inhibitor of aminopeptidase N (EC 3.4.11.2), actinonin, partially inhibited the metabolism of aspartame, alphaAsp-Phe and alphaAsp-PheNH2 by the human and pig intestinal microvillar membrane preparations, these peptides were not hydrolysed by a purifiedpreparation of aminopeptidase N. Membrane dipeptidase (EC 3.4.13.19) only hydrolysed the unblocked dipeptide, alphaAsp-Phe, but the selective inhibitor of this enzyme, cilastatin, did not block the metabolism of alphaAsp-Phe by the microvillar membrane preparations.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/11/20 alle ore 23:20:16