Question

The activation of protein kinase A by cyclic AMP binding likely occurs because of:

Please choose the correct answer from the following choices, and then select the submit answer button.


the binding of GTP to protein kinase A.

-a conformational change to protein kinase A.

t-he activity of a phosphatase.

-the phosphorylation of protein kinase A.

Answer 1

The activation of protein kinase A by cyclic AMP occurs due to a conformational change in the protein structure, allowing it to phosphorylate target substrates and initiate cellular responses.

Step-by-step explanation:

The activation of protein kinase A (PKA) by cyclic AMP (cAMP) binding likely occurs because of a conformational change to protein kinase A. This is the direct answer in two lines that address the mechanism of action. When cAMP binds to PKA, it triggers a structural reconfiguration that releases the active sites of the kinase, allowing it to phosphorylate target proteins.

cAMP is a second messenger that is synthesized by the enzyme adenylyl cyclase from ATP. When hormones like epinephrine or glucagon bind to cell surface receptors, adenylyl cyclase is activated, which increases the intracellular levels of cAMP. cAMP then binds to the regulatory subunits of PKA, leading to a conformational change that releases the catalytic subunits. These catalytic subunits are then free to phosphorylate various substrate proteins, thus modifying their activity and triggering cellular responses. This process is essential for the regulation of metabolism and other vital pathways in the cell.