Extensive enrichment of N-glycolylneuraminic acid in extracellular sialoglycoproteins abundantly synthesized and secreted by human cancer cells.

N-Glycolylneuraminic acid (Neu5Gc) is the second most populous sialic acid (Sia). The only known biosynthetic pathway of Neu5Gc is the hydroxylation of cytidine-5'-monophosphate-N-acetylneuraminic acid (CMP-Neu5Ac), catalyzed by CMP-Neu5Ac hydroxylase (CMAH). Neu5Gc is abundantly found in mammals except for human, in which CMAH is inactivated due to mutation in the CMAH gene.

Identification and partial characterization of soluble and membrane-bound KDN(deaminoneuraminic acid)-glycoproteins in human ovarian teratocarcinoma PA-1, and enhanced expression of free and bound KDN in cells cultured in mannose-rich media.

KDN (Deaminoneuraminic acid, or deaminated neuraminic acid) is a minor but biosynthetically independent member of the sialic acid. Human occurrence of KDN has already been established, although its level is so little that it is often undetectable by conventional sialic acid analysis. Elevated expression of KDN in fetal cord blood cells and some malignant tumor cells have been reported.

KDN (deaminated neuraminic acid): dreamful past and exciting future of the newest member of the sialic acid family.

KDN is an abbreviation for 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid, and its natural occurrence was revealed in 1986 by a research group including the present authors. Since sialic acid was used as a synonym for N-acylneuraminic acid at that time, there was an argument if this deaminated neuraminic acid belongs to the family of sialic acids. In this review, we describe the 20 years history of studies on KDN (KDNology), through which KDN has established its position as a distinct member of the sialic acid family.

Discovery of an alpha 2,9-PolyNeu5Ac glycoprotein in C-1300 murine neuroblastoma (clone NB41A3).

alpha2,8-PolyNeu5Ac is expressed on neural cell adhesion molecules during embryogenesis and also re-expressed on certain tumors. PolyNeu5Ac is therefore an oncodevelopmental antigen, has important regulatory effects on the adhesive and migratory behavior of neural cells, and is thus crucial to synaptic plasticity. Until now, alpha2,9-polyNeu5Ac, a linkage isomer of alpha2,8-polyNeu5Ac, has long been thought to occur only in capsules of neuroinvasive Neisseria meningitidis group C bacteria.

Endo-beta-N-acetylglucosaminidase, an enzyme involved in processing of free oligosaccharides in the cytosol.

Formation of oligosaccharides occurs both in the cytosol and in the lumen of the endoplasmic reticulum (ER). Luminal oligosaccharides are transported into the cytosol to ensure that they do not interfere with proper functioning of the glycan-dependent quality control machinery in the lumen of the ER for newly synthesized glycoproteins. Once in the cytosol, free oligosaccharides are catabolized, possibly to maximize the reutilization of the component sugars.

Dynamic change of neural cell adhesion molecule polysialylation on human neuroblastoma (IMR-32) and rat pheochromocytoma (PC-12) cells during growth and differentiation.

Polysialic acid (PSA) is a regulatory epitope of neural cell adhesion molecule (NCAM) in homophilic adhesion of neural cells mediated by NCAM, is also known to be re-expressed in several human tumors, thus serves as an oncodevelopmental antigen. In this study, using a recently developed ultrasensitive chemical method in addition to immunochemical methods, growth stage-dependent and retinoic acid (RA)-induced differentiation-dependent changes of PSA expression in human neuroblastoma (IMR-32) and rat pheochromocytoma (PC-12) cells were analyzed both qualitatively and quantitatively. Both IMR-32 and PC-12 cells expressed PSA on NCAM, and the level of PSA expressed per unit weight of cells increased with post-inoculation incubation time.

Binding of rainbow trout sperm to egg is mediated by strong carbohydrate-to-carbohydrate interaction between (KDN)GM3 (deaminated neuraminyl ganglioside) and Gg3-like epitope.

KDNalpha2-->3Galbeta4Glcbeta1Cer [(KDN)GM3] is a major (approximately 90%) component of total gangliosides found in sperm of rainbow trout (Oncorhynchus mykiss) and was shown to be present prominently at the sperm head by immunochemical staining with its specific mAb kdn3G. Liposomes containing (KDN)GM3 adhere specifically to GalNAcbeta4Galbeta4Glcbeta1Cer (Gg3Cer)-coated plastic plates. Interaction between (KDN)GM3 and Gg3Cer was much stronger than that previously observed between Neu5Acalpha2-->3Galbeta4Glcbeta1Cer and Gg3Cer.

A developmentally regulated α2,8-polysialyltransferase in embryos of the sea urchin Lytechinus pictus.

The recent chemical identification of polysialylated glycoproteins in the jelly coat and on the cell surface of the sea urchin egg raises important questions about their biosynthesis and possible function. Using CMP-[ C]-Neu5Ac as substrate and cell free preparations from eggs and embryos of the sea urchin Lytechinus pictus, we have identified a membrane associated CMP-Neu5Ac:poly-α2,8 sialosyl sialyltransferase (polyST) that transferred Neu5Ac from CMP-Neu5Ac to an endogenous acceptor membrane protein of approximately 38kDa. An average of five to six [ C]-Neu5Ac residues were transferred to the glycan moiety of this protein.