The effect of chitosan on the synthesis of l-s-nitrosocysteine that participates in the regulation of the m2 pyruvate kinase isoenzyme activity associated with ehrlich ascites cells proliferation in vitro

L-S-nitrosocysteine formation in EAT tumor cells and normal CRL-1636 cells incubated with microcrystalline chitosan was confirmed by RP-HPLC. The metabolite was identified based on UV-VIS spectra. The formation of L-S-nitrosocysteine in EAT tumor cells contributes to decreasing the level of L-cysteine in these cells. L-cysteine as an effector of the bifunctional M2 isoenzyme of pyruvate kinase (PK) initiates its histone kinase activity, which is responsible for histone H1 phosphorylation. A decrease of L-cysteine level in EAT tumor cells contributes to lack of histone H1 phosphorylation by the M2 PK isoenzyme and by the same token to inhibition of EAT cell proliferation.