Identification and characterization of N-acetylglucosamine-6-O-sulfate-specific beta1,4-galactosyltransferase in human colorectal mucosa.
6-Sulfo-sialyl Lewis X structure is attributable to recognition between lymphocytes and high endothelial venules. However, the biosynthetic pathway still remains unclear. We found that a beta-galactosyltransferase (betaGalT) in human colorectal mucosa preferentially acts on GlcNAc-6-O-sulfate (6S-GN). 6S-GN:beta4GalT was partially purified by UDP-hexanolamine-Sepharose and asialo-agalacto-ovomucin-Sepharose chromatographies. The optimum pH of this enzyme was found to be 6.5-7.5 and the Michaelis constants for 6S-GN and UDP-Gal were 0.43 mM and 16 microM, respectively. The enzymatic activity was dependent on divalent cations and the substrate specificity was not affected by alpha-lactalbumin. This is the first demonstration of the occurrence of 6S-GN:beta4GalT.
Seko
A
A
Department of Biochemistry, Sasaki Institute, and Core Research for Evolutional Science and Technology of Japan Science and Technology Corporation, Tokyo.
Hara-Kuge
S
S
Yonezawa
S
S
Nagata
K
K
Yamashita
K
K
D000117:Acetylglucosamine / Q000031:analogs & derivatives* / Q000378:metabolism; D002240:Carbohydrate Sequence; D003106:Colon / Q000166:cytology; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology*; D008969:Molecular Sequence Data; D009237:N-Acetyllactosamine Synthase / Q000378:metabolism*; D012007:Rectum / Q000166:cytology; D013379:Substrate Specificity
C033137:N-acetylglucosamine-6-sulfate; D009237:N-Acetyllactosamine Synthase; D000117:Acetylglucosamine