<p>Particles of medium- and high-molecular-weight chitosans and carboxymethyl chitosan were obtained with or without ascorbic acid. Methods were developed to obtain complexes of these particles with the plant protease papain. It was found that the activity of papain complexes with particles of carboxymethyl chitosan is significantly higher compared to its complexes with particles of chitosan. At the same time, complexes with particles of chitosan and carboxymethyl chitosan obtained with ascorbic acid showed higher values of proteolytic activity than complexes with polysaccharide particles obtained without it. Using molecular docking, it was found that amino-acid residues of papain interact with both chitosan and carboxymethyl chitosan mainly by forming hydrogen bonds and van der Waals interactions. In addition, ascorbic acid molecules and both types of polysaccharides interact with amino-acid residues from the active site of papain, Cys25 and His159, which probably contributes to an increase in the activity and stability of the enzyme in complexes with particles of chitosans and carboxymethyl chitosans, including due to the fact that ascorbic acid prevents the oxidation of the thiol group of papain, which is responsible for the act of catalysis.</p>