Question

unlabeled acetyl-coa and the following radio labeled malonyl-coa were used as substrates for fatty acid synthase. after the synthesis of palmitate (16:0), how many carbons will be labeled within the fatty acid and at what positions?

Answer 1

Acetyl-CoA and malonyl-CoA are condensed to form palmitate (16:0) through several enzymatic reactions, resulting in all 16 carbons of the fatty acid being labeled when radiolabeled malonyl-CoA is used as a substrate.

Step-by-step explanation:

The synthesis of palmitate (16:0) from unlabeled acetyl-CoA and radiolabeled malonyl-CoA involves the condensation of acetyl-CoA and malonyl-CoA units, followed by a series of enzymatic reactions.

First, the acetyl-CoA and malonyl-CoA units are transferred to an acyl carrier protein (ACP) to form acetyl-ACP and malonyl-ACP, respectively.

Next, the acetyl-ACP and malonyl-ACP undergo condensation to form acetoacetyl-ACP.

This process continues until palmitate (a 16-carbon fatty acid) is synthesized.

The labeled carbons from the radiolabeled malonyl-CoA will be present in the fatty acid at the positions corresponding to the number of condensation cycles that occurred. In this case, since palmitate has 16 carbons, all of the carbons in the fatty acid will be labeled.