MECHANISMS OF HEAT DAMAGE IN PROTEINS .I. MODELS WITH ACYLATED LYSINE UNITS

1. N-Acetyl-L-lysine showed a growth-promoting value for the young rat receiving a lysine-deficient diet approximately half that of the equivalent quantity of L-lysine; N-propionyl-L-lysine showed negligible activity. 2. Considerable quantities of lysine were recovered from acid-hydrolysis of the urine of rats receiving these two compounds. Qualitative chromatography suggested that the compounds themselves were appearing in the urine. 3. Similar results were obtained from giving proteins that had the NH2, groups of their lysine units either acetylated or propionylated. 4. Giving a pure protein in which the nutritional availability of the lysine had been reduced heat treatment resulted in greatly increased faecal lysine but little urinary lysine. © 1969, The Nutrition Society. All rights reserved.