[The tricarboxylic acid cycle and the genetic code]

Application of quantum--mechanical calculations of interaction energy of nitrous bases in DNA triplets to genetic code permits division of codons and pertinent amino acids into two groups. The first one corresponds to the upper energetic level 150-170 kJ/mole per base pair (per a triplet codon on the average). The second group corresponds to the low energetic level 88/92 kJ/mole per base pair. Comparing this grouping of amino acids with their incorporations into the cycle of tricarboxylic acids it turns out that the majority of amino acids of the first group are incorporated into the cycle via acetyl-KoA. Most amino acids of the second group are incorporated directly. It seems that the ways of amino acids introduction into the cycle of tricarboxylic acids are to a certain degree predetermined by energetic interactions of nitrous bases in the genetic codons.