Indigo-binding Domains in Cellulase Molecules

Study of cellulase adsorption on indigo particles and insoluble cellulose, as well as experiments on indigo interaction with immobilized amino acids together with theoretical analysis of three-dimensional structures of enzyme molecules, provided an evidence that certain cellulases, which have hydrophobic domains (clusters of closely located aromatic and non-polar residues) on their surface, may bind significant amounts of indigo and thus act as emulsifiers helping the dye to float out of cellulose fibers to the bulk solution in the process of enzymatic denim treatment. Only those cellulases, which had such indigo-binding domains, could efficiently remove indigo from the denim fabric providing high abrasive effects on the surface of the material.