Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
L-SERINE AND L-THREONINE DEHYDRATASE FROM CLOSTRIDIUM-PROPIONICUM - 2ENZYMES WITH DIFFERENT PROSTHETIC GROUPS
Autore:
HOFMEISTER AEM; GRABOWSKI R; LINDER D; BUCKEL W;
Indirizzi:
UNIV MARBURG,FACHBEREICH BIOL,MIKROBIOL LAB,KARL VON FRISCH STR W-3550 MARBURG GERMANY UNIV MARBURG,FACHBEREICH BIOL,MIKROBIOL LAB,KARL VON FRISCH STR W-3550 MARBURG GERMANY MAX PLANCK INST TERR MIKROBIOL MARBURG GERMANY UNIV GIESSEN,FACHBEREICH HUMANMED,INST BIOCHEM W-6300 GIESSEN GERMANY
Titolo Testata:
European journal of biochemistry
fascicolo: 2, volume: 215, anno: 1993,
pagine: 341 - 349
SICI:
0014-2956(1993)215:2<341:LALDFC>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
ESCHERICHIA-COLI K-12; PEPTOSTREPTOCOCCUS-ASACCHAROLYTICUS; ASPARTIC-ACID; PURIFICATION; IRON; DEAMINASE; PROTEINS; SEQUENCE; GLYCINE; INVITRO;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
35
Recensione:
Indirizzi per estratti:
Citazione:
A.E.M. Hofmeister et al., "L-SERINE AND L-THREONINE DEHYDRATASE FROM CLOSTRIDIUM-PROPIONICUM - 2ENZYMES WITH DIFFERENT PROSTHETIC GROUPS", European journal of biochemistry, 215(2), 1993, pp. 341-349

Abstract

L-Serine dehydratase from the Gram-positive bacterium Peptostreptococcus asaccharolyticus is novel in the group of enzymes deaminating 2-hydroxyamino acids in that it is an iron-sulfur protein and lacks pyridoxal phosphate [Grabowski, R. and Buckel, W. (1991) Eur. J. Biochem. 199, 89-94]. It was proposed that this type Of L-serine dehydratase is widespread among bacteria but has escaped intensive characterization due to its oxygen lability. Here, we present evidence that another Gram-positive bacterium, Clostridium propionicum, contains both an iron-sulfur-dependent L-serine dehydratase and a pyridoxal-phosphate-dependentL-threonine dehydratase. These findings support the notion that two independent mechanisms exist for the deamination of 2-hydroxyamino acids. L-Threonine dehydratase was purified 400-fold to apparent homogeneity and revealed as being a tetramer of identical subunits (m = 39 kDa). The purified enzyme exhibited a specific activity of 5 mukat/mg protein and a K(m) for L-threonine of 7.7 mM. L-Serine (K(m) = 380 mM) wasalso deaminated, the V/K(m) ratio, however, being 118-fold lower thanthe one for L-threonine. L-Threonine dehydratase was inactivated by borohydride, hydroxylamine and phenylhydrazine, all known inactivators of pyridoxal-phosphate-containing enzymes. Incubation with (NaBH4)-H-3specifically labelled the enzyme. Activity of the phenylhydrazine-inactivated enzyme could be restored by pyridoxal phosphate. L-Serine dehydratase was also purified 400-fold, but its extreme instability did not permit purification to homogeneity. The enzyme was specific for L-serine (K(m) = 5 mM) and was inhibited by L-cysteine (K(i) = 0.5 mM) and D-serine (K(i) = 8 mM). Activity was insensitive towards borohydride, hydroxylamine and phenylhydrazine but was rapidly lost upon exposureto air. Fe2+ specifically reactivated the enzyme. L-Serine dehydratase was composed of two different subunits (alpha, m = 30 kDa; beta, m =26 kDa), their apparent molecular masses being similar to the ones ofthe two subunits of the iron-sulfur-dependent enzyme from P asaccharolyticus. Moreover, the N-terminal sequences of the small subunits fromthese two organisms were found to be 47% identical. In addition, 38% identity with the N-terminus of one of the two L-serine dehydratases of Escherichia coli was detected.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 06:20:59