Sandbox Reserved 1165: Difference between revisions

For glucagon to initiate the breakdown of [https://en.wikipedia.org/wiki/Glycogen glycogen] into glucose, it follows a specific [https://en.wikipedia.org/wiki/Glucagon signaling mechanism] (Figure 6). Glucagon binds to a G protein-coupled receptor located on the [https://en.wikipedia.org/wiki/Cell_membrane plasma membrane], and this binding induces a [https://en.wikipedia.org/wiki/Conformational_change conformational change] that activates G proteins which exchanges a [https://en.wikipedia.org/wiki/Guanosine_diphosphate guanosine diphosphate (GDP]) for guanosine [https://en.wikipedia.org/wiki/Guanosine_triphosphate triphosphate (GTP)] that is bound to the [https://en.wikipedia.org/wiki/G_alpha_subunit alpha subunit]. Now with the GTP in place, the activated alpha subunit leaves the [https://en.wikipedia.org/wiki/Heterotrimeric_G_protein heterotrimeric G protein] and activatesthe next [https://en.wikipedia.org/wiki/Enzyme enzyme] in the cascade, [https://en.wikipedia.org/wiki/Adenylyl_cyclase adenylate cyclase]. Once adenylate cyclase is activated, it catalyzes the conversion of [https://en.wikipedia.org/wiki/Adenosine_triphosphate adenosine triphosphate (ATP)] into cyclic [https://en.wikipedia.org/wiki/Cyclic_adenosine_monophosphate adenosine monophosphate (cAMP)]. This in turn activates [https://en.wikipedia.org/wiki/Protein_kinase_A protein kinase A (PKA)] that then activates [https://en.wikipedia.org/wiki/Phosphorylase_kinase phosphorylase kinase]. Finally, the phosphorylase kinase [https://en.wikipedia.org/wiki/Phosphorylation phosphorylates] [https://en.wikipedia.org/wiki/Glycogen_phosphorylase glycogen phosphorylase b] that is then turned into its activated form, glycogen phosphorylase a. This phosphorylase A enzyme is responsible for catalyzing the release of [https://en.wikipedia.org/wiki/Glucose_1-phosphate glucose-1-phosphate] into the bloodstream from glycogen [https://en.wikipedia.org/wiki/Polymer polymers] (Figure 6).