Cloning of a novel member of the UDP-galactose:beta-N-acetylglucosamine beta1,4-galactosyltransferase family, beta4Gal-T4, involved in glycosphingolipid biosynthesis.
J Biol Chem
; 273(45): 29331-40, 1998 Nov 06.
Article
em En
| MEDLINE
| ID: mdl-9792633
ABSTRACT
A novel putative member of the human UDP-galactosebeta-N-acetylglucosamine beta1,4-galactosyltransferase family, designated beta4Gal-T4, was identified by BLAST analysis of expressed sequence tags. The sequence of beta4Gal-T4 encoded a type II membrane protein with significant sequence similarity to other beta1,4-galactosyltransferases. Expression of the full coding sequence and a secreted form of beta4Gal-T4 in insect cells showed that the gene product had beta1,4-galactosyltransferase activity. Analysis of the substrate specificity of the secreted form revealed that the enzyme catalyzed glycosylation of glycolipids with terminal beta-GlcNAc; however, in contrast to beta4Gal-T1, -T2, and -T3, this enzyme did not transfer galactose to asialo-agalacto-fetuin, asialo-agalacto-transferrin, or ovalbumin. The catalytic activity of beta4Gal-T4 with monosaccharide acceptor substrates, N-acetylglucosamine as well as glucose, was markedly activated in the presence of alpha-lactalbumin. The genomic organization of the coding region of beta4Gal-T4 was contained in six exons. All intron/exon boundaries were similarly positioned in beta4Gal-T1, -T2, and -T3. beta4Gal-T4 represents a new member of the beta4-galactosyltransferase family. Its kinetic parameters suggest unique functions in the synthesis of neolactoseries glycosphingolipids.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Glicoesfingolipídeos
/
N-Acetil-Lactosamina Sintase
Limite:
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Dinamarca