Epi SM

Epinephrine

Specifics:

• Seven Transmembrane-helix (7TM) Receptors
  • Binds with beta-adrenergic receptor
• Ligand Binding Leads to Activation of G Proteins
  • Stimulates the activity of adenlyate cyclase
    • INC concenration of the second messenger cAMP by forming it form ATP
• Unactivated state of guanyl nucleotide bound to the G protein is GDP
  • Exists as a heterotrimer consisting of alpha, beta and gamma subunits
    • Alpha and gamma subunits are usually anchored to the membrane by covalently attached fatty acids
• Exchange of the bound GDP for GTP is catalyzed by the hormone bound receptor
• Protein Kinase A activated by INC cAMP concentrations
• Phosphorylase Kinase is phosphorylated by Protein Kinase A
• Phosphorylase b is phosphorylated into Phosphorylase a by Phosphorylase Kinase