BCH 201 Assignment Question and Answers

Assignment: on BCH 201

What are Glucogenic and Ketogenic amino acids?

Write the full names and the three-letter codes, as well as the one-letter abbreviation, for each of the 20 amino acids.

Note: The structures are very important.

Number 1

KETOGENIC AND GLUCOGENIC AMINO ACIDS

Amino acids can be classified on the basis of their metabolic fate into ketogenic and glucogenic amino acids. The amino acids leading to α-ketoglutarate are glucogenic. A few amino acids are both ketogenic and glucogenic. The amino acids leading to acetyl CoA and are said to be ketogenic because they give rise to ketone bodies. They include leucine and lysine. When fed to a starved animal, ketogenic amino acids cause an increased concentration of acetoacetate and other “ketone bodies” in the blood and urine.

On the other hand, some others are glucogenic. Glucogenic amino acids are degraded to pyruvate, α-ketoglutarate, succinyl CoA, fumarate or oxaloacetate. They are called glucogenic because they lead to synthesis of glucose. When glucogenic amino acids are fed to a starved animal, they promote the synthesis of glucose. Some amino acids such as isoleucine, phenylalanine, tryptophan and tyrosine are both ketogenic and glucogenic. Mammals lack a pathway for the net synthesis of glucose from acetyl CoA. Therefore, the other fourteen amino acids are purely glucogenic amino acids.