Effects of lysine, threonine and methionine on light-driven protein synthesis in isolated pea (Pisum sativum L.) chloroplasts
Ronald Mills, W.; Wilson, K.G.
Planta 142(2): 153-160
ISSN/ISBN: 0032-0935 PMID: 24408096 DOI: 10.2307/23373526
Light-driven incorporation of [14C]leucine (LEU) into protein in isolated pea chloroplasts was inhibited by 0.1 and 1 mM lysine (LYS), 0.1-10 mM threonine (THR) and 1 mM methionine (MET). Equimolar combinations of LYS plus THR were inhibitory at both 0.1 and 0.5 mM. Incorporation of [14C]aspartic acid (ASP) and [3H]tyrosine (TYR) was also reduced by 1 mM LYS or THR. In the cases tested, LYS and/or THR inhibitions were partially or fully reversed by 0.1 mM MET. [35S]MET incorporation was unaffected or stimulated by LYS and THR. The hypothesis that MET is biosynthesized in isolated chloroplasts and that its synthesis is regulated by LYS and/or THR was supported. Of 16 other amino acids tested at 1 mM, isoleucine, phenylalanine, tryptophan, tyrosine and valine inhibited protein synthesis.