Molecular cloning and characterization of beta1,4-N-acetylgalactosaminyltransferases IV synthesizing N,N'-diacetyllactosediamine.
A sequence highly homologous to beta1,4-N-acetylgalactosaminyltransferase III (beta4GalNAc-T3) was found in a database of human expressed sequence tags. The full-length open reading frame of the gene, beta4GalNAc-T4 (GenBank accession number AB089939), was cloned using the 5' rapid amplification of cDNA ends method. It encodes a typical type II transmembrane protein of 1039 amino acids having 42.6% identity with beta4GalNAc-T3. The recombinant enzyme transferred N-acetylgalactosamine to N-acetylglucosamine-beta-benzyl with a beta1,4-linkage to form N,N'-diacetyllactosediamine as did beta4GalNAc-T3. In specificity toward oligosaccharide acceptor substrates, it was quite similar to beta4GalNAc-T3 in vitro, however, the tissue distributions of the two enzymes were quite different. These results indicated that the two enzymes have similar roles in different tissues.
Gotoh
Masanori
M
Glycogene Function Team, Research Center for Glycoscience, National Institute of Advanced Industrial Science and Technology (AIST), Open Space Laboratory Central-2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan.
Sato
Takashi
T
Kiyohara
Katsue
K
Kameyama
Akihiko
A
Kikuchi
Norihiro
N
Kwon
Yeon-Dae
YD
Ishizuka
Yasuko
Y
Iwai
Toshie
T
Nakanishi
Hiroshi
H
Narimatsu
Hisashi
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002240:Carbohydrate Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004187:Disaccharides / Q000096:biosynthesis*; D006801:Humans; D007785:Lactose / Q000031:analogs & derivatives* / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D017350:N-Acetylgalactosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013379:Substrate Specificity; D014018:Tissue Distribution
D004187:Disaccharides; C093701:N-acetylgalactosaminyl-1-4-N-acetylglucosamine; C484901:B4GALNT4 protein, human; D017350:N-Acetylgalactosaminyltransferases; C023220:(N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase; D007785:Lactose