The Net Utilization of Non-Specific Nitrogen Sources for the Synthesis of Non-Essential Amino Acids

Abstract

The effectiveness of a mixture of essential L-amino acids, single non-essential amino acids, diammonium citrate, urea and biuret as a source of nitrogen for the biosynthesis of non-essential amino acids was investigated. These nitrogenous compounds were added at isonitrogenous levels to a mixture of essential amino acids, patterned after the composition of the rat carcass. The amino acids were present exclusively in the L form. L-Glutamic acid and a mixture of L-essential amino acids were the most effective supplements when judged by such criteria as growth response, food efficiency and net nitrogen utilization. These were followed by alanine, aspartic acid, asparagine, proline, glutamine, diammonium citrate, urea, biuret, glycine and serine, all arranged in order of their effectiveness. Diets containing L-hydroxyproline caused depression in growth rate.