Purification and properties of lysyl- and methionyl-soluble ribonucleic acid synthetases from wheat germ

Abstract

Lysyl-s-RNA synthetase (l-lysine: s-RNA ligase (AMP), EC 6.1.1.6) and methionyl-s-RNA-synthetase (l-methionine: s-RNA ligase (AMP), EC 6.1.1.10) were purified from wheat germ about 600-fold and 160-fold, respectively. The two enzymes catalyse amino acid-dependent ATP-pyrophosphate exchange as well as the incorporation of amino acids into s-RNA. The pH optimum of lysine enzyme is in the range 6.8–7.1 and that of methionine enzyme in the range 8.1–8.5. Both enzymes are strongly inhibited by p-hydroxymercuribenzoate and the activity is restored by sulfhydryl group-containing compounds.