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Titolo:
Kinetic basis for the donor nucleotide-sugar specificity of beta 1,4-N-acetylglucosaminyltransferase III
Autore:
Ikeda, Y; Koyota, S; Ihara, H; Yamaguchi, Y; Korekane, H; Tsuda, T; Sasai, K; Taniguchi, N;
Indirizzi:
Osaka Univ, Sch Med, Dept Biochem, Suita, Osaka 5650871, Japan Osaka UnivSuita Osaka Japan 5650871 Biochem, Suita, Osaka 5650871, Japan
Titolo Testata:
JOURNAL OF BIOCHEMISTRY
fascicolo: 4, volume: 128, anno: 2000,
pagine: 609 - 619
SICI:
0021-924X(200010)128:4<609:KBFTDN>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
N-ACETYLGLUCOSAMINYLTRANSFERASE-III; BLOOD-GROUP-A; GAMMA-GLUTAMYL-TRANSPEPTIDASE; ASPARAGINE-LINKED OLIGOSACCHARIDES; RAT-LIVER CARCINOGENESIS; GLYCOPROTEIN-SYNTHESIS; HEN OVIDUCT; SUBSTRATE-SPECIFICITY; GROUP-B; GENE TRANSFECTION;
Keywords:
N-acetylglucosaminyltransferase; bisecting GlcNAc; GnT-III; nucleotide-sugar; substrate specificity;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Taniguchi, N Osaka Univ, Sch Med, Dept Biochem, 2-2 Yamadaoka, Suita, Osaka 5650871, Japan Osaka Univ 2-2 Yamadaoka Suita Osaka Japan 5650871 871, Japan
Citazione:
Y. Ikeda et al., "Kinetic basis for the donor nucleotide-sugar specificity of beta 1,4-N-acetylglucosaminyltransferase III", J BIOCHEM, 128(4), 2000, pp. 609-619

Abstract

The kinetic basis of the donor substrate specificity of beta 1,4-N-acetylglucosaminyltransferase III (GnT-III) was investigated using a purified recombinant enzyme. The enzyme also transfers GalNAc and Glc moieties from their respective UDP-sugars to an acceptor at rates of 0.1-0.2% of that for GlcNAc, but Gal is not transferred at a detectable rate. Kinetic analyses revealed that these inefficient transfers, which are associated with the specificity of the enzyme, are due to the much lower V-max values, whereas the K-m values for UDP-GalNAc and UDP-Glc differ only slightly from that for UDP-GlcNAc. It was also found that various other nucleotide-Glc derivatives bind to the enzyme with comparable affinities to those of UDP-GlcNAc and UDP-Glc, although the derivatives do not serve as glycosyl donors. Thus, GnT-IIIdoes not appear to distinguish UDP-GlcNAc from other structurally similar nucleotide-sugars by specific binding in the ground state. These findings suggest that the specificity of GnT-III toward the nucleotide-sugar is determined during the catalytic process. This type of specificity may be efficient in preventing a possible mistransfer when other nucleotide-sugars are present in excess over the true donor.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 07:42:37