The enzymatic sulphation of heparan sulphate by hen's uterus |
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Authors: | Alan H Johnson John R Baker |
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Institution: | Department of Biochemistry, Trinity College, Dublin 2 Irish Republic |
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Abstract: | A sulphotransferase preparation from hen's uterus catalysed the transfer of sulphate from adenosine 3′-phosphate 5′-sulphatophosphate to N-desulphated heparan sulphate, heparan sulphate, N-desulphated heparin and dermatan sulphate. Heparin, chondroitin sulphate and hyaluronic acid were inactive as substrates for the enzyme. N-desulphated heparin was a much poorer substrate for the enzyme than N-desulphated heparan sulphate suggesting that properties of the substrate other than available glucosaminyl residues influenced enzyme activity. N-acetylation of N-desulphated heparin and N-desulphated heparan sulphate reduced their sulphate acceptor properties so it was unlikely that the N-acetyl groups of heparan sulphate facilitated its sulphatiion. Direct evidence for the transfer of 35S]sulphate to amino groups of N-desulphated haparan sulphate was obtained by subsequent isolation of glucosamine from heparan 35S]sulphate product. This was made possible through the use of a flavobacterial enzyme preparation which contained “heparitinase” activity but had been essentially freed of sulphatases. Attempts to transfer 35S]sulphate to glucosamine or N-acetylglucosamine were unsuccessfull. |
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Keywords: | PAPS adenosine 3′-phosphate 5′-sulphatophosphate APS adenosine 5′- sulphatophosphate |
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