Effect of Essential Amino Acid-deficiency on Protein Nutrition

Adult rats were fed a tryptophan-defficient diet containing 20% oxidized casein for 9 days and the changes of the specific activities of both free- and protein-bound methionine in the liver and muscle in process of time was compared with rats paired-fed a 20%, casein diet. The specific activities of whole liver protein from 1 to 9 hr after intraperitoneal injection of 35S-methionine were significantly enhanced for the deficient group. On the other hand, incorporation of methionine into crude liver albumin and into muscle proteins seemed not to be significantly changed under the experimental conditions.