Initiation of altered heparan sulphate on beta-D-xyloside in rat hepatocytes.
Inhibition of protein synthesis by cycloheximide 10(-3)M reduced the incorporation of [35S]sulphate into heparan sulphate to about 5% of untreated hepatocytes. Addition of rho-nitrophenyl beta-D-xyloside could partially revert this inhibitory effect. The sulphated material isolated from the cell layer or secretions of hepatocytes grown in presence of cycloheximide and rho-nitrophenyl beta-D-xyloside were shown to be mostly free heparan sulphate chains not bound to core protein. Covalent association of beta-xylosides to the heparan sulphates was demonstrated for heparan sulphate synthetized in the presence of [35S]sulphate, cycloheximide and the fluorogenic 4-methylumbelliferyl beta-D-xyloside. Beta-Xylosides served as an initiator of heparan sulphate chain synthesis in rat hepatocytes only in the absence of protein synthesis. Heparan sulphates primed on artificial beta-xylosides are slightly smaller in molecular size and are more sulphated than chains linked to core protein.
D000818:Animals; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D006025:Glycosaminoglycans / Q000096:biosynthesis*; D006027:Glycosides / Q000494:pharmacology*; D006497:Heparan Sulfate / Q000096:biosynthesis*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D013462:Sulfur Radioisotopes; D014316:Tritium
D003513:Cycloheximide; D006025:Glycosaminoglycans; D006027:Glycosides; D006497:Heparan Sulfate; D013462:Sulfur Radioisotopes; D014316:Tritium; C008646:4-nitrophenyl beta-D-xyloside