Effect of sugars on amino acid biosynthesis in maize root tips

Abstract

There is a general increase in incorporation of acetate carbon when excised maize root tips are aged for 3 h in a salts medium, but little further increase during a subsequent 3-h period. Addition of glucose or sucrose to the medium causes a further increase in the incorporation of acetate carbon into glutamic acid, glutamine, γ-amino butyric acid and into the protein amino acids, principal among these being glutamic, aspartic, proline, threonine, valine and the leucines. Sugars also cause a reduced incorporation of acetate carbon into asparagine. The results indicate that glucose (or sucrose) has a major effect in diverting carbon of the tricarboxylic acid cycle into glutamine and protein amino acids and away from asparagine.