Currently, in molecular biology, special attention is paid to the study of so-called connective proteins, in particular regulators of cell growth and reproduction processes - various classes of proteinases. A large group is represented by kininogens - they are divided into an independent subgroup. To date, more than 15 variants of the connective protein, similar in their characteristics to kininogen, have been identified and described. The structural basis is made up of 2 and 5 cysteine amino acids. Combined into one peptide, they perform the function of a coenzyme (i.e., a molecule directly involved in metabolism), consisting of residues of the methyl groups of cysteine and glutamic acid nitrogen (Fig. 4. Sequence of amino acid units).
It is quite difficult to identify the primary structure of kininogens, because its