An obese patient had failed to lose weight because he could

An obese patient had failed to lose weight because he could not follow prescribed weight reduction diets. Consequently, he volunteered to go on a starvation diet as part of a study of amino acid metabolism. Blood samples were taken and analyzed for plasma amino acids during a 6 week fast. Valine, leucine and isoleucine were transiently increased during the first week but dropped below initial levels at later times. A total of 13 amino acids ultimately decreased in plasma at the end of the study. The largest decrease was seen for alanine, which rapidly dropped 70% during the first week. Total plasma amino nitrogen dropped only 12%.

What is the source of the plasma (alpha)-aminobutyrate?

Solution

Alpha amino butyrate is also known as homoalanine. In the biosynthesis of isoleucine there is a component namely oxytobutyrate which upon transamination results in formation of homoalanine.