- The chitosan derivatives (carboxymethylchitosan and N -(2-hydroxy)propyl-3-trimethylammoniumchitosan) with molecular weight of 200, 350, and 600 kDa were synthesized. The ficin complexes with chitosan and the aforementioned derivatives were prepared. IR spectra of chitosan, carboxymethylchitosan, N ‑(2-hydroxy)propyl-3-trimethylammoniumchitosan, and their complexes with ficin were recorded. An analysis of these spectra confirmed a formation of the conjugates between the macromolecules of polysaccharides and ficin. The optimum ratio of the protein content (0.7 mg/g of the carrier) and the special activity (1590 units/mg of the protein) was found after a formation of the ficin complex with N -(2-hydroxy)propyl-3-trimethylammoniumchitosan with a molecular weight of 350 kDa. The efficacy of the formation of the complex of ficin (according to the special catalytic activity) with N -(2-hydroxy)propyl-3-trimethylammoniumchitosan (350 kDa) was higher than that for chitosan (350 kDa) and carboxymethylchitosan (350 kDa) by 2.4 and 9.8 times, respectively. Types of interactions, energy of the first binding, amino acid composition of the ficin surfaces which contacted with the carriers during the complex formation were studied by the method for a molecular docking. The bonds and interactions with chitosan and its derivatives were found to be formed, in particular, with a participation of the amino acid residues that were placed near the ficin active site (Cys25 and His162). This fact explained a change in the proteolytic activity of the prepared complexes. The complexes of ficin with N -(2-hydroxy)propyl-3-trimethylammoniumchitosan were soluble in a wide pH range of the medium and could be more promising (than the ficin–chitosan complexes) for a design of medicines and biocatalysts for the food, brewing, and tanning industry.