H. Habuchi et al., PURIFICATION AND CHARACTERIZATION OF HEPARAN-SULFATE 6-SULFOTRANSFERASE FROM THE CULTURE-MEDIUM OF CHINESE-HAMSTER OVARY CELLS, The Journal of biological chemistry, 270(8), 1995, pp. 4172-4179
Heparan sulfate 6-sulfotransferase, which catalyzes the transfer of su
lfate from S'-phosphoadenylyl sulfate to position 6 of N-sulfoglucosam
ine in heparan sulfate, was purified 10,700-fold to apparent homogenei
ty with a 40% yield from the serum-free culture medium of Chinese hams
ter ovary cells. The isolation procedure included affinity chromatogra
phy of the first heparin-Sepharose CL-GB column (stepwise elution), 3'
,5'-ADP-agarose, and the second heparin-Sepharose CL-6B column (gradie
nt elution). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis
of the purified enzyme showed two protein bands with molecular masses
of 52 and 45 kDa. Both proteins appeared to be glycoproteins, because
their molecular masses decreased after N-glycanase digestion. When co
mpletely desulfated and N-resulfated heparin was used as acceptor, the
purified enzyme transferred sulfate to position 6 of N-sulfoglucosami
ne residue but did not transfer sulfate to the amino group of glucosam
ine residue or to position 2 of the iduronic acid residue. Heparan sul
fate was also sulfated by the purified enzyme at position 6 of N-sulfo
glucosamine residue. Chondroitin and chondroitin sulfate did not serve
as accepters. The optimal pH for enzyme activity was around 6.3. The
enzyme activity was inhibited by dithiothreitol and was stimulated str
ongly by protamine. The K-m, value for adenosine S'-phosphate 5'-phosp
hosulfate was 0.44 mu M.