Biosynthesis of acid mucopolysaccharides by the surviving new born rat skin. II. - Specific labelling of individual monosaccharides from (U14C)-glucose. Metabolic origin of L-iduronic acid.
1)Individual monosaccharides (uronic acids and aminosugars) have been purified following specific hydrolysis of the mucopolysaccharides from new born rat skin (hyaluronic acid, heparin + heparan sulfate, chondroitin sulfate A, B and C), after incubation with [U14C]-glucose under various conditions and for varying incubation periods. The yields and the specificity of the methods used for hydrolysis are discussed. 2) Monosaccharides from hyaluronic acid and the sulfated mucopolysaccharide fraction are labelled at an approximately equal rate. In addition, high rates of labelling of glucosamine isolated from the sulfated fractions confirms the preferential labelling of (heparin + heparan sulfate) demonstrated with the sulfated polymers. 3) In all fractions, aminosugars are considerably less labelled than the corresponding uronic acids, which suggests the existence of endogeneous diluting precursor pools for the former monosaccharides. 4) No drift of radioactivity from D-glucuronate to L-iduronate could be demonstrated in sulfated mucopolysaccharides after inhibition of their biosynthesis by puromycin or diluting the labelled precursor pools. Hence it has not been possible to substantiate on the surviving tissue the C5 epimerization at the polymer level, as previously demonstrated by other authors with subcellular fractions of various origin.
D000818:Animals; D000831:Animals, Newborn; D005947:Glucose / Q000378:metabolism; D006025:Glycosaminoglycans / Q000096:biosynthesis*; D006595:Hexosamines / Q000378:metabolism; D007067:Iduronic Acid / Q000096:biosynthesis; D011691:Puromycin / Q000494:pharmacology; D051381:Rats; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D014574:Uronic Acids / Q000378:metabolism
D006025:Glycosaminoglycans; D006595:Hexosamines; D014574:Uronic Acids; D007067:Iduronic Acid; D011691:Puromycin; D005947:Glucose