And so we have two catalytic and two regulatory subunits. And so we represent the inactive form of PKA with the following format. So R two, C two complex basically means we have two regulatory subunits one, two and two catalytic subunits one and two. So as we mentioned previously, under stressful situations the Adrian medulla is stimulated and it releases the epinephrine hormone. And the epinephrine hormone basically stimulates the production of cyclic adenosine monophosphate camp. And it's the Tamp that is the allosteric regulator of PKA.