Abstract
1. The role of UDP-xylose in the regulation of corneal glycosaminoglycan biosynthesis was investigated. Bovine corneas were incubated with [U-14C]-glucose in the presence and in the absence of the nucleotide, and the radioactivity of chondroitin, chondroitin sulphate and keratan sulphate, as well as of their monosaccharide constituents, was determined. 2. A decrease in the rate of biosynthesis of chondroitin and chondroitin sulphate and an increase in that of keratan sulphate were observed in the samples incubated with UDP-xylose. 3. The UDP-glucuronic acid isolated after the incubation in the presence of UDP-xylose showed a noticeable decrease in the amount of radioactivity incorporated; this result suggests that UDP-xylose inhibits the UDP-glucose dehydrogenase, causing an accumulation of UDP-glucose and consequently an increase in the formation of UDP-galactose and keratan sulphate. 4. Galactose and galactosamine isolated from the polysaccharides showed variations in the amount of radioactivity incorporated in accordance with those observed for the macromolecules; this fact confirms that in the system we used in vitro a real biosynthesis of the polysaccharide chain took place and that the regulatory effect of UDP-xylose was active at the monosaccharide level.
Full text
PDF




Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- FEINGOLD D. S., NEUFELD E. F., HASSID W. Z. The 4-epimerization and decarboxylation of uridine diphosphate D-glucuronic acid by extracts from Phaseolus aureus seedlings. J Biol Chem. 1960 Apr;235:910–913. [PubMed] [Google Scholar]
- Fransson L. A. Structure of dermatan sulfate. IV. Glycopeptides from the carbohydrate-protein linkage region of pig skin dermatan sulfate. Biochim Biophys Acta. 1968 Mar 11;156(2):311–316. [PubMed] [Google Scholar]
- KAPLAN D., MEYER K. Ageing of human cartilage. Nature. 1959 May 2;183(4670):1267–1268. doi: 10.1038/1831267a0. [DOI] [PubMed] [Google Scholar]
- LINDAHL U., RODEN L. THE ROLE OF GALACTOSE AND XYLOSE IN THE LINKAGE OF HEPARIN TO PROTEIN. J Biol Chem. 1965 Jul;240:2821–2826. [PubMed] [Google Scholar]
- Mathews M. B., Cifonelli J. A. Comparative biochemistry of keratosulfates. J Biol Chem. 1965 Nov;240(11):4140–4145. [PubMed] [Google Scholar]
- Mathews M. B. Macromolecular evolution of connective tissue. Biol Rev Camb Philos Soc. 1967 Nov;42(4):499–551. doi: 10.1111/j.1469-185x.1967.tb01528.x. [DOI] [PubMed] [Google Scholar]
- NEUFELD E. F., HALL C. W. INHIBITION OF UDP-D-GLUCOSE DEHYDROGENASE BY UDP-D-XYLOSE: A POSSIBLE REGULATORY MECHANISM. Biochem Biophys Res Commun. 1965 May 3;19:456–461. doi: 10.1016/0006-291x(65)90146-4. [DOI] [PubMed] [Google Scholar]
- PERLMAN R. L., TELSER A., DORFMAN A. THE BIOSYNTHESIS OF CHONDROITIN SULFATE BY A CELL-FREE PREPARATION. J Biol Chem. 1964 Nov;239:3623–3629. [PubMed] [Google Scholar]
- Robert L., Parlebas J. Biosynthèse in vitro des glycoprotéines de la cornée. Bull Soc Chim Biol (Paris) 1965;47(10):1853–1866. [PubMed] [Google Scholar]
- Robinson H. C., Telser A., Dorfman A. Studies on biosynthesis of the linkage region of chondroitin sulfate-protein complex. Proc Natl Acad Sci U S A. 1966 Dec;56(6):1859–1866. doi: 10.1073/pnas.56.6.1859. [DOI] [PMC free article] [PubMed] [Google Scholar]