Glycogen synthetase and phosphorylase activity in slow and fast twitch skeletal muscle fibres in man.
Glycogen synthetase (I + D) and  phosphorylase (à + b) activity was determined in human skeletal muscle biopsies with different muscle fibre composition and in dissected an pooled batches of the two main muscle fibre types: slow twitch (ST) and fast twitch (FT), respectively. Glycogen synthetase (I + D) activity remained unchanged as the per cent of FT fibres increased, but phosphoyrlase (à + b) activity was found to increase. A similar activity pattern was found in dissected and FT fibres as compared to ST fibres, i.e. the same glycogen synthetase activity but heightened phosphoyrlase activity.
D000328:Adult; D006006:Glycogen Synthase / Q000378:metabolism*; D006801:Humans; D009132:Muscles / Q000032:analysis / Q000201:enzymology*; D006005:Phosphorylases / Q000378:metabolism*
D006005:Phosphorylases; D006006:Glycogen Synthase