[Study of three-dimensional structure of proteins by means of tritium labeling. I. Free amino acids as a model of residues in an unfolded polypeptide chain].

Probabilities of the incorporation of tritium label into various amino acids with alanine as a standard have been determined by "bombing" solid targets with a 3H-atom beam (2 000 K). The results show that amino acids can be used with sufficient accuracy as models of amino acid residues in a polypeptide chain under 100%, accessibility. The resulting coefficients, if taken into consideration in the analysis of intramolecular distribution of tritium in short tryptic peptides of TMV protein, will yield an equiprobable distribution in the case when the label has been introduced into a peptide. The distribution is not uniform, however, if a labelled peptide has been isolated from an "irradiated" hydrolysate protein.