The amino acid sequence of rabbit skeletal muscle glycogenin

The amino acid sequence of glycogenin from rabbit skeletal muscle has been determined. The N‐acetylated protein consists of 332 amino acids and has a molecular mass of 37278 Da. The novel tyrosyl‐glucose linkage between glycogenin and glycogen [Smythe, C., Caudwell, F. B., Ferguson, M. & Cohen, P. (1988) EMBO J. 7, 2681–2686] is shown to occur at a single site, tyrosine‐194. Although glycogenin is a UDP‐Glc utilising glucosyltransferase that self‐glucosylates [Pitcher, J., Smythe, C. & Cohen, P. (1988) Eur. J. Biochem. 176, 391–395], following addition by an unknown enzyme of the first glucose to tyrosine‐194, it is not homologous to either human glycogen synthase or other UDP‐Glc‐requiring enzymes.