Physiology 3140A Chapter Notes -Glycogen Phosphorylase, Muscle Relaxant, Glycogen Synthase
4 Feb 2014
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Need at least 10-7 [camp] to activate pathways: primary physiological function is to serve as intracellular second messenger to bind. & activate protein kinase a (pk-a: another role acts as ligand for a specific class of odorant cation channels in olfactory neurons. Adenylate cyclase: membrane bound protein, found at plasma membrane, consists of 2 alternating hydrophobic & hydrophilic domains, hydrophobic domains each containing 6 membrane-spanning domains, hydrophilic regions having 2 catalytic domains. In general stimulating by gs and inhibited by gi: multiple isoforms, at least 1 isoform complexes with calcium bound calmodulin leading to modulation of enzymes activity, converts atp to camp = [camp] Inactive pk-a is a hetero-tetrameric complex: 2 catalytic subunits, 2 regulatory subunits, heterotetramer inactive form high binding affinity to catalytic subunits catalytic domains are hidden within regulatory subunit. First molecule of camp alters the ability of 2nd molecule of camp to bind.
