The Biosynthesis of Chondroitin Sulphate INCORPORATION OF SULPHATE INTO CHONDROITIN SULPHATE IN EMBRYONIC CHICK CARTILAGE

Journal/Book: Biochem. J. (1960) 78 620 Printed in Great Britain. 1960;

Abstract: New South Wales State Cancer Council Special Unit for Investigation and Treatment Prince of Wales Hospital Randwick N.S.W. Australia (Received 16 November 1959) SUMMARY 1. Crude hyaluronic acid from human umbilical cords stimulated the synthesis of chondroitin sulphate in a particle-free enzyme system derived from embryonic-chick cartilage. This stimulation was demonstrated to be due to a complex of chondroitin sulphate C and protein present in the umbilical cords. Treatment with proteolytic enzymes gave the free mucopolysaccharide which retained the stimulating activity. 2. Chondroitin Sulphate C stimulated chondroitin sulphate synthesis to a greater degree than chondroitin sulphate A. The mucoprotein isolated from the embryonic-chick cartilage was composed of 70 % of mucopolysaccharide and 30 % of protein. Infrared data showed that the former was mainly chondroitin sulphate A and probably contained small quantities of the C isomer. This mucoprotein bovine-nasal-cartilage mucoprotein chondroitin and hyaluronic acid failed to stimulate chondroitin sulphate synthesis. 3. Upon treatment of the chick-cartilage extract with protamine to remove acid mucopolysaccharides chondroitin sulphate A and C possessed equal stimulating power when tested with this extract. This indicates that relative saturation of the normal cartilage extract with chondroitin sulphate A-type components accounts for the higher degree of activity obtained with chondroitin sulphate C. Chondroitin sulphate B which does not occur in cartilage could not replace chondroitin sulphate A or C in ability to stimulate [35S]sulphate incorporation into chondroitin sulphate in the mucopolysaccharide-deficient extract. 4. Depolymerization of chondroitin sulphate C by short treatment with testicular hyaluronidase led to a marked increase in stimulating activity. Reduction of terminal aldehyde groups of this preparation did not alter its activity. 5. A priming mechanism of synthesis of isomeric chondroitin sulphates is proposed which is typespecific. ___MH

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