PURIFICATION OF CHONDROITIN 6-SULFOTRANSFERASE SECRETED FROM CULTUREDCHICK-EMBRYO CHONDROCYTES

Chondroitin 6-sulfotransferase, which transfers sulfate from 3'-phosph oadenylyl sulfate to position 6 of N-acetylgalactosamine in chondroiti n, was purified 1,430-fold to apparent homogeneity with a 22% yield fr om the serum-free culture medium of chick embryo chondrocytes by affin ity chromatography on heparin-Sepharose CL-6B, wheat germ agglutinin-a garose, and 3',5'-ADP-agarose. Sodium dodecyl sulfate-polyacrylamide g el electrophoresis of the purified enzyme showed a single broad protei n band with an apparent molecular weight of 75,000. Since the purified enzyme has an apparent molecular weight of 160,000 as judged by gel c hromatography on Superose 12, the active form of chondroitin 6-sulfotr ansferase may be a dimer. The purified enzyme transferred sulfate to c hondroitin, chondroitin sulfate, and corneal keratan sulfate. Chondroi tin sulfate E from squid cartilage, dermatan sulfate, and heparan sulf ate hardly served as acceptors of the sulfotransferase. The sulfated p roduct derived from keratan sulfate was degraded by keratanase but not by chondroitinase ABC.