Synthesis of a chitosan-based functional biopolymer with both catalytic and binding groups for protein and DNA hydrolysis

Abstract

A novel chitosan-based biopolymer (CCMS) containing both catalytic and binding groups for protein and DNA hydrolysis was designed and prepared in this study. The catalytic center, consisting of 1,4,7,10-tetraazacyclododecane (cyclen) coordinated with Cu(II), was constructed on the chitosan microspheres prepared by reverse-phase suspension crosslinking. A pendant aldehyde was introduced to the biopolymer as the binding group in view of its ability to form imine bonds with the amino groups of exposed on the surface of the protein substrate. FTIR analysis showed that the two functional groups were introduced to the biopolymer, which hydrolyzed all protein and DNA substrates tested in the study. The unique microenvironment on the surface of CCMS, imparted by the polysaccharide backbone, was conducive to peptide and phosphodiester bond cleavage. In addition, CCMS featured a desirable stability and can be reused for four times with minimal loss of proteolytic and DNA cleavage activity.