title: Enhancing enzyme stability against TiO2-UV induced inactivation.
abstract: The use of enzymes in conjunction with inorganic photocatalysts requires stability against photooxidation. In this paper, we describe enhanced stabilization of a model enzyme, chymotrypsin, to photooxidation driven by titanium dioxide exposed to ultraviolet light (TiO(2)-UV). Stabilization is achieved conjugating the enzyme with an oligomeric adduct of UV-absorbing (2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate) (HBMA) and free radical-absorbing 2-methacryloyloxyethyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylate (Trolox-HEMA). Juxtaposition of the antioxidant Trolox with the UV absorber HBMA within a single chain reduced the rate of deactivation of the former by TiO(2)-UV. This enables modified enzyme, which is adsorbed on TiO(2), to absorb both UV-light and free radicals and locally reduce the rate of photooxidation. Interestingly, Trolox was more readily deactivated by TiO(2)-UV when it was conjugated separately to chymotrypsin that had been pre-modified with HBMA moieties.
authors.affiliation: McGowan Institute for Regenerative Medicine and Department of Bioengineering, 100, Technology Drive, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA.
authors.forename: Bhalchandra S
authors.initials: BS
authors.lastname: Lele
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Russell
mesh_terms: D000042:Absorption; D002384:Catalysis; D002918:Chymotrypsin / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects*; D004795:Enzyme Stability / Q000528:radiation effects; D046911:Macromolecular Substances / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D046911:Macromolecular Substances; C009495:titanium dioxide; D014025:Titanium; D002918:Chymotrypsin