Enzymic synthesis of ϵ-N-acetyl-l-lysine

Abstract An enzyme which is capable of synthesizing ϵ- N -acetyl- l -lysine from l -lysine and acetyl phosphate has been purified from beef liver. However, the possibility that this enzyme is identical with ornithine transcarbamylase could not be proved definitely. Studies show that it has no apparent co-factor requirements and that its optimum pH is about 8.6. The enzymic activity is greatly inhibited by phosphate ion, and the activation energy for acetylation of l -lysine is 4.9 kcal. The enzyme reacts with l -ornithine at a slightly faster rate and with a lower K m than with l -lysine. The biochemical significance of the enzyme and its product, ϵ- N -acetyl- l -lysine, is discussed in relation to the early stages of l -lysine metabolism in mammals and microorganisms.