Mechanism of activation of a G protein-coupled receptor. When the hormone activates the receptor, the inactive a, b, and g G protein complex associates with the receptor and is activated, with an exchange of guanosine triphosphate (GTP) for guanosine diphosphate (GDP). This causes the a subunit (to which the GTP is bound) to dissociate from the b and g subunits of the G protein and to interact with membrane-bound target proteins (enzymes) that initiate intracellular signals.
Activation of enzymes
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.