ABSTRACT
A two-step method was developed to homogeneously insert carbonic anhydrase (CA, E.C. 4.2.1.1) into Michael-adduct-based coatings. CA was first covalently coupled to an N-vinylformamide-based water-soluble polymer. Unlike native CA, the resulting polymer/CA system could be dispersed within a film matrix. The enzyme-containing coating (ECC) hydrolyzes p-nitrophenyl propionate in buffered media at high rates retaining approximately 7% apparent activity. In comparison, other two-step techniques for the chemical coupling of CA to the coating surface were less efficient and led to coatings with significantly less activity. A three-step immobilization process coupling the enzyme to the surface of a partially hydrolyzed coating also raised retention of activity after coating synthesis. CA-ECC is stable under ambient conditions retaining 45% activity after 90 days of storage at room temperature.
Subject(s)
Carbonic Anhydrases/chemistry , Coated Materials, Biocompatible/chemistry , DNA Adducts , Carbonic Anhydrases/metabolism , Coated Materials, Biocompatible/metabolism , DNA Adducts/chemical synthesis , Drug Stability , Hot Temperature , Neurotensin/chemistry , Surface PropertiesABSTRACT
Recent events have emphasized the threat from chemical and biological warfare agents. Within the efforts to counter this threat, the biocatalytic destruction and sensing of chemical and biological weapons has become an important area of focus. The specificity and high catalytic rates of biological catalysts make them appropriate for decommissioning nerve agent stockpiles, counteracting nerve agent attacks, and remediation of organophosphate spills. A number of materials have been prepared containing enzymes for the destruction of and protection against organophosphate nerve agents and biological warfare agents. This review discusses the major chemical and biological warfare agents, decontamination methods, and biomaterials that have potential for the preparation of decontamination wipes, gas filters, column packings, protective wear, and self-decontaminating paints and coatings.
Subject(s)
Biocompatible Materials/metabolism , Biodegradation, Environmental , Biological Warfare , Bioterrorism , Chemical Warfare Agents/metabolism , Chemical Warfare , Decontamination/methods , Decontamination/instrumentation , Protective DevicesABSTRACT
The synthesis of water-borne polyurethane coatings in the presence of diisopropylfluorophosphatase (DFPase, E.C. 3.8.2.1) enabled the irreversible attachment of the enzyme to the polymeric matrix. The distribution of immobilized DFPase as well as activity retention are homogeneous within the coating. The resulting enzyme-containing coating (ECC) film hydrolyzes diisopropylfluorophosphate (DFP) in buffered media at high rates, retaining approximately 39% intrinsic activity. Decreasing ECC hydrophilicity, via the use of a less hydrophilic polyisocyanate during polymerization, significantly enhanced the intrinsic activity of the ECC. DFPase-ECC has biphasic deactivation kinetics, where the initial rapid deactivation of DFPase-ECC leads to the formation of a hyperstable and active form of enzyme.
Subject(s)
Coated Materials, Biocompatible/chemical synthesis , Enzymes, Immobilized/chemistry , Esterases/chemistry , Phosphoric Triester Hydrolases , Polyurethanes/chemistry , Diffusion , Enzyme Activation , Enzyme Stability , Reproducibility of Results , Sensitivity and Specificity , Solubility , Substrate Specificity , Temperature , Water/chemistryABSTRACT
We report herein an efficient method to control pH in reactions catalyzed by hydrolytic enzymes, such as the degradation of paraoxon by phosphotriesterase (E.G. 3.1.8.1; OPH), using urease-catalyzed (E.G. 3.5.1.5) urea hydrolysis as a buffering agent. Given the distinct pH profiles of urease and OPH activities, urease produces base on demand in response to pH drop during paraoxon detoxification. As pH changes, the enzyme activities fluctuate to finally stabilize at a pH "set-point," where the rates of acid and base generation are equal. By varying the urease to OPH ratio, various pH "set-points" ranging between 6.5 and 8.5 were achieved within minutes and could be predicted theoretically. This dynamic approach for pH control was successfully applied to the development of a positive-response inhibition-based sensor.
