Zara J, Hagen F K, Ten Hagen K G, Van Wuyckhuyse B C, Tabak L A
Department of Dental Research, School of Medicine and Dentistry, University of Rochester, New York 14642, USA.
Biochem Biophys Res Commun. 1996 Nov 1;228(1):38-44. doi: 10.1006/bbrc.1996.1613.
A novel isoform of UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase, designated ppGaNTase-T3, has been cloned from a mouse testis cDNA library and expressed in COS7 cells. ppGaNTase-T3 displayed 64 and 59% amino acid identity with ppGaNTase-T1 and ppGaNTase-T2, respectively, and 96% amino acid identity with the recently reported human form of ppGaNTase-T3. The ppGaNTase-T3 transcript is abundant in the major salivary glands, gastrointestinal tract and both the male and female reproductive systems. ppGaNTase-T3 and ppGaNTase-T1 display overlapping substrate preferences in vitro, although mapping studies of O-glycosylated peptides suggests that certain hydroxyamino acids are preferentially glycosylated by each isoform. This suggests that more than one isoform of ppGaNTase may be required to complete the O-glycosylation of endogenous substrates.
一种新型的UDP-N-乙酰半乳糖胺：多肽N-乙酰半乳糖胺基转移酶同工型，命名为ppGaNTase-T3，已从小鼠睾丸cDNA文库中克隆出来并在COS7细胞中表达。ppGaNTase-T3与ppGaNTase-T1和ppGaNTase-T2的氨基酸同一性分别为64%和59%，与最近报道的人源ppGaNTase-T3的氨基酸同一性为96%。ppGaNTase-T3转录本在主要唾液腺、胃肠道以及男性和女性生殖系统中均丰富表达。尽管对O-糖基化肽的定位研究表明某些羟基氨基酸优先被每种同工型糖基化，但ppGaNTase-T3和ppGaNTase-T1在体外表现出重叠的底物偏好性。这表明可能需要不止一种ppGaNTase同工型来完成内源性底物的O-糖基化。
