Akey intermediate in the catabolism of fatty acids with uneven numbers of carbon atoms is

Propionly CoA

Explanation:

During oxidation of odd chain fatty acids, the odd chain are oxidized exactly in the same manner as even chains. However, after successive removal of 2 carbon units, at the end, one 3-carbon unit, propionyl CoA is formed.

Propionyl CoA is a product of beta oxidation of odd chain fatty acids.

In three steps reaction propionyl-CoA can be converted to succinyl-CoA, an intermediate of the citric acid cycle which is converted to oxaloacetate, and is used for gluconeogenesis.

cell regulation is conducted by special proteins.