Amino acid-dependent exchange between pyrophosphate and adenosine triphosphate in root nodules

Abstract

An extract prepared from root nodules of Galega officinalis (Linn.) contained amino acid-activating enzymes. Valine, leucine and isoleucine were most rapidly activated by the extract; the rates of activation of phenylalanine, serine, lysine, arginine and tyrosine were low while the rates of activation of histidine, cysteine, tryptophan, alanine and threonine were somewhere between the high rates of the former group of amino acids and the low rates of the latter. The other amino acids were not activated. The sum of the activities of the individual amino acids was greater than the activity of the mixture of 18 amino acids. Manganese partially replaced magnesium as activator for the enzyme, but neither cobalt nor molybdate could replace magnesium.