Enzyme Conjugation to the Polysaccharide Chitosan:  Smart Biocatalysts and Biocatalytic Hydrogels

• Published in: Bioconjugate chemistry 2001-03, Vol.12 (2), p.301-306
• Main Authors: Vazquez-Duhalt, Rafael, Tinoco, Raunel, D'Antonio, Paul, Topoleski, L. D. Timmie, Payne, Gregory F
• Format: Article
• Language: English
• Subjects: Biopolymers - chemistry; Catalysis; Chitin - analogs & derivatives; Chitin - chemistry; Chitosan; Cross-Linking Reagents - chemistry; Enzyme Stability; Glutaral - chemistry; Hydrogels - chemical synthesis; Hydrogels - chemistry; Hydrogen-Ion Concentration; Kinetics; Laccase; Molecular Structure; Oxidoreductases - chemistry; Oxidoreductases - metabolism
• ISSN: 1043-1802; 1520-4812
• DOI: 10.1021/bc000095u

Laccase from Coriolopsis gallica was conjugated to the renewable biopolymer chitosan using carbodiimide chemistry. The laccase−chitosan conjugate was observed to offer three unique properties. First, the laccase−chitosan conjugate displayed pH-responsive behavior such that the conjugate was soluble and active under acidic conditions, but precipitated when the pH was raised toward neutrality. Second, the laccase−chitosan conjugate was more stable than free laccase at extreme pHs. At pH 1, the inactivation rate constant (k in) for the soluble laccase−chitosan conjugate was 20-fold less than that for free laccase. At pH 13, k in for the insoluble laccase−chitosan conjugate was nearly 3-fold less than that for free laccase. Finally, the laccase−chitosan conjugate could be cross-linked under mild conditions to create biocatalytic hydrogels. Potential benefits for enzyme−chitosan conjugates are discussed.