Question

Suppose that each β–adrenergicβ–adrenergic receptor bound to epinephrine converts 100100 molecules of the GαGα subunit to the GTP-bound form, Gαs.Gαs.

If each molecule of activated adenylate cyclase produces 1000 molecules of cAMP per second, how many molecules of cAMP are produced in 10 seconds10 seconds after the formation of a single complex between epinephrine and the β–adrenergicβ–adrenergic receptor? Assume the pathway is fully responsive.

Molecules of cAMP = ??

Answer 1

since 1 epinephrine activates 100 G alpha subunits. one G alpha subunits activate 1 adenylate cyclase, so 100 G alpha subunits will activate 100 adenylate cyclase.

1 adenylate cyclase makes 1000 cAMP in 1 second. then 100 adenylate cyclase will make 100*1000 = 100000 cAMP per second.

So the total number of cAMP produced in 10 seconds = 100000 cAMP/sec * 10 sec = 1000000 = 10⁶ cAMP