Proglycogen: A low‐molecular‐weight form of muscle glycogen

FEBS Letters

Lomako, Wieslawa M.¹  Lomako, Joseph¹  Whelan, William J.¹ 

[1] Department of Biochemistry and Molecular Biology, University of Miami, Miami, FL 33101, USA

关键词: Glycogenin;    Glycogen biogenesis;    Protein glucosylation;    Proglycogen;   

DOI  :  10.1016/0014-5793(91)80154-U

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We recently reported that muscle contains a trichloroacetic acid-precipitable component having M _r approx. 400 kDa that can be glucosylated by an endogenous enzyme acting on UDPglucose. This component contains within itself the autocatalytic, self glucosylating protein glycogenin, the primer for glycogen synthesis. We now report that this substance, to which we give the name proglycogen, is a glycogen-like molecule constituting about 15% or total glycogen. It acts as a very efficient acceptor of glucose residues added from UDPglucose. Further, that the endogenous enzyme that adds the glucose to proglycogen is not the autocatalytic protein but a glycogen synthase-like enzyme. Proglycogen may be an intermediate in the synthesis and degradation of macromolecular glycogen and may exist and be metabolized as a separate entity. Consideration should now be given to the revival of the concept that tissue contains two forms of glycogen. One is proglycogen. The other is the ‘classical’, macromolecular glycogen. Additionally, proglycogen and glycogen may be glucosylated by different forms of synthase.

【 授权许可】

Unknown