Two glycogen synthase activities associated with proteoglycogen in retina

被引：5

作者：

Curtino, JA ^{[1
]}

Lacoste, ER ^{[1
]}

机构：

[1] UNC, Fac Ciencias Quim, CIQUIBIC,Dept Quim Biol Dr Ranwel Caputto, Ctr Invest Quim Biol Cordoba, RA-5016 Cordoba, Argentina

来源：

NEUROCHEMICAL RESEARCH | 2000年 / 25卷 / 01期

关键词：

glycogen synthase; proteoglycogen; retina glycogen synthase; retina proteoglycogen; proteoglycogen biosynthesis; glycogenin;

D O I：

10.1023/A:1007551802426

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Glycogen synthase of bovine retina was found associated with the acid-insoluble and acid-soluble proteoglycogen fractions. The synthase associated with the acid-insoluble proteoglycogen precursor showed an 8-fold lower Km for UDP-glucose than the synthase associated with the acid-soluble fraction, and was inhibited by detergent. A short digestion with pronase resulted in conversion of the acid insoluble fraction into acid-soluble. The results lead us to postulate that the acid-insolubility of the proteoglycogen fraction and the association with retina membrane proposed before, is caused by glycogen synthase strongly associated to its polysaccharide moiety. The enlargement of the polysaccharide moiety during proteoglycogen biosynthesis, from glycogenin linked to a few 11 to 12 glucose units to the acid-insoluble proteoglycogen precursor (Mr 470,000) would be carried out, together with the branching enzyme, by the glycogen synthase showing a low Km for UDP-glucose. The glycogen synthase with the highest Km for UDP-glucose would participate in conversion of the precursor into mature acid-soluble proteoglycogen.

引用

页码：129 / 132

页数：4

共 11 条

[1] EVIDENCE FOR THE GLYCOPROTEIN NATURE OF RETINA GLYCOGEN [J].