Histidine and Its Anticodon GpUpG are Similar Metabolic Reaction Rate Enhancers: Molecular Origin of the Genetic Code

Abstract

Using spectrophotometry, it was found that histidine enhances weakly but specifically various metabolic reaction rates such as pyruvate carboxylase, oxalacetate decarboxylase and glucose-6-phosphate isomerase (indicating that only one of the twenty amino acids is catalytic). Oligo-ribonucleotides having flexible dihedral angles could also be expected to be rate enhancers in these metabolic reactions. The survey by spectrophotometry showed that GpUpG, an anticodon of histidine, is also a similar rate enhancer. The formation of the reaction products in the cases of pyruvate carboxylase and oxalacetate decarboxylase was furthermore confirmed by thin-layer chromatography using ¹⁴C-labeled pyruvate and by high-performance liquid chromatography. The origin of the genetic code may thus be based on direct molecular relationships between amino acids and anticodons.