So in the absence of the allosteric effect of the cyclic adenosine monophosate molecule the coronary structure consists of two catalytic sites and these are shown in green as well as two regulatory sites. And these are shown in light brown. So this is basically one of these regulatory subunits and this is the other regulatory subunit. 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.