The initiation of glycogen biosynthesis in rat heart α‐1,4 glucans tightly associated with glycogen synthase
A partially purified glycogen synthase from rat cardiac muscle transferred glucosyl residues from UDP‐[14C]glucose to an endogenous protein acceptor in the absence of added primer. After native gel electrophoresis of the enzyme preparation, unprimed activity was detected. Primer‐dependent and indepe...
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1986
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00142956_v156_n1_p163_BLUMENFELD http://hdl.handle.net/20.500.12110/paper_00142956_v156_n1_p163_BLUMENFELD |
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| Sumario: | A partially purified glycogen synthase from rat cardiac muscle transferred glucosyl residues from UDP‐[14C]glucose to an endogenous protein acceptor in the absence of added primer. After native gel electrophoresis of the enzyme preparation, unprimed activity was detected. Primer‐dependent and independent activities were found in the same position. After denaturing gel electrophoresis of the reaction products, radioactivity comigrated with protein. Pulse‐chase experiments showed that the size of the reaction products increased as a function of time. These products were degraded by amyloglucosidase, thus suggesting that glycogen‐like molecules had grown on the protein acceptor. The activity of the enzyme was markedly reduced upon preincubation with α‐amylase. Therefore, preformed protein‐bound α‐1,4‐glucans were acting as primers. The glucoprotein acceptor may be a protein strongly associated with glycogen synthease, or alternatively, the enzyme itself. Copyright © 1986, Wiley Blackwell. All rights reserved |
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