| 1. |
- Ångström, Jonas, 1950, et al.
(författare)
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Chemical characterization of penta-, hexa-, hepta-, octa-, and nonaglycosylceramides of rat small intestine having a globoside-like terminus.
- 1982
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Ingår i: The Journal of biological chemistry. - 0021-9258. ; 257:2, s. 682-8
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Tidskriftsartikel (refereegranskat)abstract
- A novel series of glycosphingolipids has been isolated from the nonepithelial part of rat small intestine. A mixed fraction containing 3 major components corresponding to glycolipids with 5, 6, and 7 sugars and 2 minor components with 8 and 9 sugars was characterized. The structure of the major components was deduced by mass spectrometry and proton NMR spectroscopy of nondegraded permethylated and permethylated-reduced (LiAlH4) derivatives and gas-liquid chromatography of degradation products of native, permethylated, and permethylated-reduced glycolipids. The structures of the penta-, hexa-, and hepta-glycosylceramides were found to be GalNAcp beta 1 leads to (3Galp alpha 1 leads to)2-44Galp beta 1 leads to 4Glcp beta 1 leads to 1Cer. By analogy reasoning, supported by mass spectrometry, the octa- and nonaglycosylceramides were concluded to have 1 and 2 additional internal leads to 3Galp alpha 1 leads to 3 structures, respectively. A pentaglycosylceramide fraction from another rat strain was also isolated. The NMR spectra were in agreement with 2 isomeric structures of which 1 had the internal alpha 1 leads to 4 linkage replaced by an alpha 1 leads to 3 linkage. The fatty acids of all components were nonhydroxy 16:0 to 24:0 acids with the 18:0 homologue as dominating species. The major base was sphingosine and possibly monohydroxy 18:1 base in the larger glycolipids. This is a novel series of structures with a terminal saccharide identical with isoglobotetraoxylceramide (cytolipin R). The glycosyltransferase for the terminal GalNAc beta 1 leads to 3 of cytolipin R may possibly be identical with the enzyme adding the terminal sugar of this novel series. This is supported by the presence in the same tissue of probable precursor glycolipids with 4 to 8 hexoses.
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| 2. |
- Ångström, Jonas, 1950, et al.
(författare)
-
Separation and characterization of hematosides with different sialic acids and ceramides from rat small intestine. Different composition of epithelial cells versus non-epithelial tissue and of duodenum versus jejunum-ileum.
- 1981
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Ingår i: Journal of biochemistry. - 0021-924X. ; 90:4, s. 909-21
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Tidskriftsartikel (refereegranskat)abstract
- The hematosides (sialyl-lactosylceramides) of rat small intestine were separated as their acetylated derivatives. The isolated fractions were characterized by mass spectrometry and degradative methods, and the two major fractions also by NMR spectroscopy. From these results hematosides with different sialic acid and ceramide type could be assigned to thin-layer chromatographic bands. This allowed a structural interpretation of the chromatographic patterns observed for different parts of the small intestine. Thus, epithelial cells of ileum contained only hematoside with N-glycoloylneuraminic acid. Duodenum lacked this compound and instead the epithelial cells contained hematoside with N-acetylneuraminic acid. In non-epithelial tissue or both duodenum and jejunum-ileum the major hematoside had N-acetyl-neuraminic acid. The hematosides of epithelial cells had ceramide containing 18 : 0 trihydroxy base combined with 16, 20, 22, 24 : 0, and 24 : 1 hydroxy fatty acids (major part) or non-hydroxy fatty acids. In the non-epithelial hematosides the ceramide consisted of 18 : 1 dihydroxy base combined with 16, 18, 20, 22, 24 : 0, and 24 : 1 non-hydroxy fatty acids.
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