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Titolo:
ACYL TRANSFER ACTIVITY OF AN AMIDASE FROM RHODOCOCCUS SP. STRAIN R312- FORMATION OF A WIDE-RANGE OF HYDROXAMIC ACIDS
Autore:
FOURNAND D; BIGEY F; ARNAUD A;
Indirizzi:
ECOLE NATL SUPER AGRON MONTPELLIER,INST NATL RECH AGRON F-34060 MONTPELLIER 01 FRANCE ECOLE NATL SUPER AGRON MONTPELLIER,INST NATL RECH AGRON F-34060 MONTPELLIER 01 FRANCE
Titolo Testata:
Applied and environmental microbiology
fascicolo: 8, volume: 64, anno: 1998,
pagine: 2844 - 2852
SICI:
0099-2240(1998)64:8<2844:ATAOAA>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
ENANTIOMER-SELECTIVE AMIDASE; NITRILE HYDRATASE; STRUCTURAL EVIDENCE; PURIFICATION; EXPRESSION; CLONING; INHIBITORS; GENE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
D. Fournand et al., "ACYL TRANSFER ACTIVITY OF AN AMIDASE FROM RHODOCOCCUS SP. STRAIN R312- FORMATION OF A WIDE-RANGE OF HYDROXAMIC ACIDS", Applied and environmental microbiology, 64(8), 1998, pp. 2844-2852

Abstract

The enantioselective amidase from Rhodococcus sp, strain R312 was produced in Escherichia coli and was purified in one chromatographic step. This enzyme was shown to catalyze the acyl transfer reaction to hydroxylamine from a wide range of amides, The optimum working pH values were 7 with neutral amides and 8 with alpha-aminoamides. The reaction occurred according to a Ping Pong Bi Bi mechanism. The kinetic constants demonstrated that the presence of a hydrophobic moiety he the carbonside chain considerably decreased the K-mamide values (e.g., K-mamide= 0.1 mM for butyramide, isobutyramide, valeramide, pivalamide, hexanoamide, and benzamide), Moreover, very high turnover numbers (k(cat)) were obtained with linear aliphatic amides (e.g., k(cat) = -333 s(-1) with hexanoamide), whereas branched-side-chain-, aromatic cycle- or heterocycle-containing amides were sterically hindered. Carboxylic acids, alpha-amino acids, and methyl esters mere not acyl donors or were very bad acyl donors. Only amides and hydroxamic acids, both of which contained amide bonds, mere determined to be efficient acyl donors. On the other hand, the highest affinities of the acyl-enzyme complexes forhydroxylamine were obtained with short, polar or unsaturated amides as acyl donors (e.g., Km(NH2OH) = 20, 25, and 5 mM for acetyl-, alanyl-and acryloyl-enzyme complexes, respectively). No acyl acceptors except water and hydroxylamine were found. Finally, the purified amidase was shown to be L-enantioselective towards alpha-hydroxy- and alpha-aminoamides.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/04/20 alle ore 09:36:21