title: Oxidation, photosensitized by certain diketones, of enzymes and protection against such oxidation by histidine derivatives.
abstract: Bovine milk lactoperoxidase, eel acetylcholinesterase, and Aeromonas aminopeptidase were photooxidized and inactivated in broad-spectrum visible light in the presence of 2,3-butanedione and 1-phenyl-1,2-propanedione. Methylglyoxal caused similar effects at 254 nm. 2-Thiol-L-histidine and 3-methyl-L-histidine protected the enzymes against photoinactivation more effectively then N3-, even at a molar ratio of 2:1 (protector to enzyme). These compounds also delayed the photoinactivation of acetylcholinesterase, induced by ultraviolet light.
mesh_terms: D000110:Acetylcholinesterase / Q000528:radiation effects*; D000626:Aminopeptidases / Q000528:radiation effects*; D000818:Animals; D002417:Cattle; D003931:Diacetyl / Q000494:pharmacology; D006639:Histidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D007784:Lactoperoxidase / Q000528:radiation effects*; D008027:Light; D008762:Methylhistidines / Q000494:pharmacology; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000528:radiation effects*; D011765:Pyruvaldehyde / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D008762:Methylhistidines; C034197:2-thiolhistidine; D006639:Histidine; D011765:Pyruvaldehyde; D007784:Lactoperoxidase; D010544:Peroxidases; D000110:Acetylcholinesterase; D000626:Aminopeptidases; D003931:Diacetyl; C028118:3-methylhistidine