Synthesis of a novel chitosan-based Ce(IV) complex with proteolytic activity in vitro toward edible biological proteins

Abstract

The occurrence of enzymatic activities is attributed to proper spatial organization of functional groups from first principles. A novel chitosan-based Ce(IV) complex (CC[Ce(IV)]), an artificial metalloproteinase, was synthesized by attaching cyclen, Ce(IV), and chlorophyll-Cu(II) to a chitosan-based matrix. The enzymatic hydrolytic efficiency (HE) and the procedure of catalyzing myoglobin (Mb) by CC[Ce(IV)] in vitro were investigated using spectrophotometry, electrophoresis, and liquid chromatography. The results showed that the HE of Mb was up to 60% at 60°C within 24h, displaying a catalytic proficiency. The pseudo-first-order kinetic constant (kobs) for CC[Ce(IV)] treatment within 24h was 3.85×10(-2)h(-1), higher than that for α-chymotrypsin treatment, which was 2.63×10(-2)h(-1). Moreover, the peptide bond derived from Asp-Phe/Phe-Asp in Mb could be specifically cleaved by CC[Ce(IV)], which could simulate the functionality of α-chymotrypsin. This work provides an experimental basis for potential utilization of the chitosan-based Ce(IV) complexes in the food industry.

Keywords: Acetic acid (PubChem CID: 176); Acetonitrile (PubChem CID: 6342); Artificial metalloproteinases; Ce(IV); Ceric(IV) ammonium nitrate (PubChem CID: 56841022); Chitosan; Cleavage; Coomassie brilliant blue G250 (PubChem CID: 6333920); Cyclen; Epichlorohydrin (PubChem CID: 7835); Formaldehyde (PubChem CID: 712); Glutaraldehyde (PubChem CID: 3485); Ninhydrin (PubChem CID: 10236); Peptide bonds; Span 80 (PubChem CID: 5385498); Trichloroacetic acid (PubChem CID: 6421).