Now, the first question is what exactly is the quarterly structure of protein kinase A when it is not bound to the cyclic Amp? What is the inactive quarter structure of protein kinase A? So this is basically shown on the board. So in its inactive form, PKA consists of two types of subunits. So just like aspartate transcarbomolase atcase consists of catalytic and regulatory subunits, our PKA also consists of catalytic and regulatory subunits. Now, the catalytic subunit contains the active side while the regulatory subunit contains that allosteric side that binds onto the cyclic Amp.