Fish egg glycophosphoproteins have species-specific N-linked glycan units previously found in a storage pool of free glycan chains.
Fish egg glycophosphoproteins have species-specific N-linked glycan units previously found in a storage pool of free glycan chains.
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DOI：
10.1016/s0021-9258(18)35763-6
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发表时间：
1992-12
期刊：
影响因子：
--
通讯作者：
M. Iwasaki;A. Seko;K. Kitajima;Y. Inoue;S. Inoue
中科院分区：
文献类型：
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作者：
M. Iwasaki;A. Seko;K. Kitajima;Y. Inoue;S. Inoue
Recent findings (Ishii, K., Iwasaki, M., Inoue, S., Kenny, P. T. M., Komura, H., and Inoue, Y. (1989) J. Biol. Chem. 264, 1623-1630; Inoue, S., Iwasaki, M., Ishii, K., Kitajima, K., and Inoue, Y. (1989) J. Biol. Chem. 264, 18520-18526) of a relatively large quantity of complex-type free sialo-oligosaccharides in the unfertilized eggs of freshwater fish, Plecoglossus altivelis and Tribolodon hakonensis, prompted us to search for their progenitor glycoproteins. First we demonstrated a third occurrence of free sialoglycans in the unfertilized eggs of Medaka fish (Oryzias latipes). Next, in all three species studied, a uniformly high level of glycophosphoproteins (GPP) was identified and found to possess N-linked glycan units. The carbohydrate structures of the GPP were determined to be identical with those of the free glycans isolated from the unfertilized eggs of the respective fish species. Thus, the most likely candidate for the progenitor of free sialoglycans appeared to be the oocyte GPPs. This implies that the liberation of the free glycans by a putative peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase may represent a necessary biochemical event during vitellogenesis or oogenesis. The present results may provide insight into a new concept of a “protein N-glycosylation/de-N-glycosylation system” recently proposed by us (Seko, A., Kitajima, K., Inoue, Y., and Inoue, S. (1991) J. Biol. Chem. 266, 22110-22114).
