Partial phosphorylation of muscle phosphorylase. II. Formation of a hybrid phosphorylase in vivo

Pál Gergely, György Bot, Edit F. Kovács

Research output: Contribution to journalArticle

23 Citations (Scopus)


The conversion of phosphorylase b (1,4-α-d-glucan:orthophosphate α-glucosyltransferase, EC to phosphorylase a has been investigated in rabbit and frog skeletal muscle in vivo. It was found that hybrid phosphorylase (containing phosphorylated and non-phosphorylated subunits) is formed in vivo through the effects of hormonal and electrical stimulation. The stimulation in all cases leads to the conversion of the total amount of phosphorylase b to hybrid phosphorylase, i.e. phosphorylase b does not remain in the stimulated muscle. Hybrid phosphorylase is an allosteric sensitive enzyme species, it may be activated by AMP in the absence and in the presence of ATP, too. Therefore AMP and ATP may play a regulatory role, because ATP inhibits the activity of phosphorylase b in resting muscle but it does not inhibit the activity of hybrid phosphorylase. The possibility of this mechanism will be also discussed in this paper.

Original languageEnglish
Pages (from-to)78-84
Number of pages7
JournalBBA - Enzymology
Issue number1
Publication statusPublished - Nov 25 1974


ASJC Scopus subject areas

  • Medicine(all)

Cite this