title: Nucleotidic cofactors and the origin of the genetic code.
abstract: In this article it is suggested that the first coding system started from specific interactions between the nucleotide part of nucleotidic cofactors and enzymes. These interactions generated a first primitive code of four words of one letter each for the four primittive amino acids (phenylalanine, lysine, glycine and proline); when the triplet code (which allowed the integration of 20 amino acids into proteins) progressively appeared, it must have been modulated by the existence of this first coding system.
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D003067:Coenzymes; D004247:DNA; D005823:Genetics; D009711:Nucleotides; D012313:RNA
chemical_list: D003067:Coenzymes; D009711:Nucleotides; D012313:RNA; D004247:DNA