AMINO-ACID-SEQUENCE AND EXPRESSION OF THE HEPATIC GLYCOGEN-BINDING (G(L))-SUBUNIT OF PROTEIN PHOSPHATASE-1

A full-length cDNA encoding the putative hepatic glycogen-binding (G(L )) subunit of protein phosphatase-1 (PP1) was isolated from a rat live r library, The deduced amino acid sequence (284 residues, 32.6 kDa) wa s 23% identical (39% similar) to the N-terminal region of the glycogen -binding (G(M)) subunit of PP1 from striated muscle, The similarities between G(M) and G(L) were most striking between residues 63-86, 144-1 66 and 186-227 of human G(M) (similar to 40% identity), nearly all the identities with the putative yeast homologue GAC1 being located betwe en 144-166 and 186-227. The cDNA was expressed in E. coli, and the exp ressed protein transformed the properties of PP1 to those characterist ic of the hepatic glycogen-associated enzyme. These experiments establ ish that the cloned protein is G(L).