Answer:
The overall strategy employed in the catabolism of the carbon skeletons of the 20 amino acids is conversion to citric acid intermediates such as acetyl-CoA
Explanation:
The breakdown of the different carbon skeletons of the 20 amino acids is strategically channelled towards the citric acid cycle. Six major products are obtained in the catabolism of the carbon chain of amino acids and these products all enter the citrc acid cycle. The six major products are acetyl-CoA, α-ketoglutarate, succinyl-CoA, fumarate, oxaloacetate and pyruvate.
The amino acids that are broken down completely into acetoacetyl-CoA and/or acetyl-CoA are said to be ketogenic since they yield ketone bodies in the liver.
The amino acids that are broken down into α-ketoglutarate, succinyl-CoA, fumarate, oxaloacetate and pyruvate can be converted to glucose and glycogen and are said to be glucogenic. Pyruvate can further be converted to either acetyl-CoA or oxaloacetate. Some amino acids though are both ketogenic and glucogenic, e.g. tryptophan, threonine.
