Question

What changes in fatty acid metabolism would result from a mutation in the muscle carnitine acyltransferase I in which the mutant protein has lost its affinity for malonyl-CoA but not its catalytic activity?
A. Fatty acid synthesis in the mitochondria and fatty acid oxidation in the cytosol could occur simultaneously.
B. Fatty acid synthesis in the cytosol and fatty acid oxidation in the mitochondria could occur simultaneously.
C. Synthesis of malonyl carnitine could only occur at high malonyl-CoA concentration.
D. Synthesis of malonyl-CoA would no longer be inhibited carnitine.

Answer 1

Answer:

B. Fatty acid synthesis in the cytosol and fatty acid oxidation in the mitochondria could occur simultaneously.

Explanation:

Carnitine acyltransferase I, is a mitochodrial enzyme also known as Carnitine palmitoyltransferase I (CPT1).

The acyl group is transferred to carnitine by the cytoplasmic form of the enzyme by Carnitine acyltransferase I

Malonyl coA would no longer inhibit fatty acid entry into the mitochondrion and beta oxidation, so there might be a futile cycle of simultaneous fatty acid synthesis in the cytosol and fatty acid breakdown in mitochondria.