The amino acid requirements of man. X. The lysine requirement
Journal of Biological Chemistry
Two of the earlier papers of this series dealt with the minimal requirements of adult man for tryptophan (1) and phenylalanine (2) , as measured by the maintenance of nitrogen equilibrium. In continuation of this program, attention was next directed to the lysine needs of the human organism. This amino acid is of special interest since many vegetable proteins have a low content or are practically devoid of it. Particularly is this true of certain cereal proteins which serve as important
... s important constituents of human dietaries. Hence, the question of the minimal lysine requirement of man assumes unusual significance. The experiments outlined in the following pages demonstrate that surprisingly small quantities of this amino acid suffice, at least for the maintenance of nitrogen equilibrium in adults. EXPERIMENTAL Elsewhere, the reader will find detailed descriptions of the methods used in the conduct of the experiments (3, 1). In the present investigation, the customary procedures were followed except with respect to the composition of the amino acid mixtures. Throughout the entire program of human studies, the make-up of these mixtures has been modified progressively, as experience warranted, in order thereby to conserve supplies of costly materials.