| Autor: |
Berthillier, Gisèle, Azzar, Gérard J.-C., Got, René |
| Předmět: |
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| Zdroj: |
European Journal of Biochemistry; Feb75 Part 1, Vol. 51 Issue 1, p275-282, 8p |
| Abstrakt: |
Microsomal preparations from rat liver mediate transfer of glucosyl units from UDP-glucose to three different kinds of acceptors: an endogenous glycoprotein, exogenous glycogen and collagen. Both glucosyl transferases work at acidic pH, 6.5 for transfer on endogenous acceptor and glycogen and at pH 5.5 for transfer on collagen. None of these enzymes require divalent cations for activity. While transfers on endogenous acceptor and glycogen are inhibited by the presence of a non-ionic detergent. Triton X-100, the transfer on collagen is activated by the same detergent. Glycogen-synthase activity requires glucose 6-phosphate at an optimal concentration of 1 mM. The Km values glycogen and collagen.Characterisation of the product indicates that a protein-bound α1-4 glucan is formed when no primer is added. Enzymatic and acidic hydrolyses of radioactive glycogen and collagen show only glucose as a radioactive sugar identified by thin layer chromatography on cellulose.Pre-treatment of microsomal membranes by α-analyse demonstrates that glucosyltransferases are not absorbed on endogenous glycogen and seem to be really membranous enzymes. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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