Xyl Beta Research Articles

Characterization of a novel glycosphingolipid, ceramide nonasaccharide, isolated from spermatozoa of the fresh water bivalve, Hyriopsis schlegelii.

A new glycosphingolipid, provisionally named Lipid III in our previous work (Hori, T., Sugita, M., Kanbayashi, J., and Itasaka, O. (1977) J. Biochem. (Tokyo) 81, 107-114), was extracted and purified from the spermatozoa of the fresh water bivalve, Hyriopsis schlegelii. The yield of the glycolipid was 1.8 mg/g dry weight of the spermatozoan preparation. Its chemical structure was characterized by compositional analysis, partial acid hydrolysis, methylation analysis, and proton nuclear magnetic resonance spectroscopy. The following structure is proposed: 3-O-MeFuc alpha 1 leads to 2.3-O-MeXyl beta 1 leads to 4(3-O-MeGalNAc alpha 1 leads to 3)Fuc alpha 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3(Xyl beta 1 leads to 2)Man beta 1 leads to 4Glc beta 1 leads to 1Cer. This glycolipid contains the same backbone as the pentaglycosyl ceramide (Lipid II) reported previously (Hori, T., Takeda, H., Sugita, M., and Itasaka, O. (1977) J. Biochem. (Tokyo) 82, 1281-1285). Lipid III is structurally related to Lipid II by linking it with a fucose and three kinds of O-methyl sugars, namely, 3-O-methylxylose, 3-O-methylfucose, and 3-O-methyl-N-acetylgalactosamine, through an internal fucose moiety. Unlike most vertebrate glycolipids, Lipid III appears to be unique in having an internal fucose and O-methyl sugars as well as mannose. To our knowledge, this is the first instance for the natural occurrence of 3-O-mehylxylose. Aliphatic constituents of the lipid are palmitic acid and stearic acid as the principal fatty acids, and octadeca-4-sphingenine as the major long chain base.

Studies on glycosphingolipids of fresh-water bivalves. VI. Isolation and chemical characterization of neutral glycosphingolipids from spermatozoa of the fresh-water bivalve, Hyriopsis schlegelii.

The spermatozoa of the fresh-water bivalve, Hyriopsis schlegelii, had a complex spectrum of neutral glycosphingolipids. CDS, CTS, CTeS were isolated as minor components (together they accounted for 3% of the total neutral glycolipid fraction), while CMS and the glycolipids (Lipid I, II, and III) with larger saccharide chains that were previously characterized (1--4) occurred as major ones. The chemical structures were determined by employing exoglycosidases, partial acid hydrolysis and permethylation analysis. The proposed structures are as follows: Man alpha(1-3)Man beta(1-4)Glc-Cer for CTS, and Man alpha(1-3)[Xyl beta(1-2)]Man beta(1-4)Glc-Cer for CTeS. CTeS was the first example of a tetraglycosyl ceramide containing xylose. In another fraction, two types of diglycosyl ceramides were obtained as a mixture, and identified as Man beta(1-4)Glc-Cer and Gal beta(1-4)Glc-Cer, respectively. The long-chain base was predominantly composed of sphingosine, and the acyl groups were mainly of palmitate and stearate.

Complete structure of the carbohydrate moiety of stem bromelain. An application of the almond glycopeptidase for structural studies of glycopeptides.

Asparagine-linked oligosaccharides of stem bromelain glycopeptides were quantitatively released by digestion with the almond glycopeptidase which cleaves beta-aspartylglycosylamine linkage in glycopeptides with oligopeptide moieties. The primary structures of the two oligosaccharide components, (Man)3(Xyl)1(Fuc)1(GlcNAc)2 and (Man)2-(Xyl)1(Fuc)1(GlcNAc)2 were elucidated as Man alpha 1 leads to 6Man alpha 1 leads to 6[Xyl beta 1 leads to 2]Man beta 1 leads to 4GlcNAc beta 1 leads 4[Fuc alpha 1 leads to 3]GlcNAc and Man alpha 1 leads to 6[Xyl beta 1 leads to 2]Man beta 1 leads to 4 GlcNAc beta 1 leads to 4[Fuc alpha 1 leads to 3] GlcNAc, respectively.