Biopolymers and cell. 1997; 13 (3): 191 - 196

The prototropic tautomerism of nitrogen bases: a new insight into the old problem

D. M. Hovorun

The summary is made of the scries of calculation-theoretical investigations fulfilled by the setniempirical quantum-chemical AMI method on physico-chemical features of prototropic tautomerism of nucleotide bases. Applying of non-traditional approach which is based on the view that highest possible numbers of prototropic tautomers of bases are determined by an overall Quantity of protons and electron lone pairs of proton acceptor atoms, the success was achieved in ascertaining that as regards prototropic tautomerism nudcotule bases are more mobile structures (prototropic tautomerism of nucleotide bases has a molecular-zwitterionic diameter involving carboprotons as well) than it was assumed earlier. A biological significance of the data obtained, which are generalized and may be extended from the autlwr's point of view to larmier range of objects, ammo acids included.