title: Spectroscopic determination of acetylcholine esterase-inhibitor complex: determination of conformational shifts of proteins.
abstract: Changes in the absorbance spectrum of tetraphenylporphyrin sulfonate (TPPS) are observed that are unique for the proteins lysozyme, luciferase, apomyoglobin, myoglobin, gamma globulin, insulin, RNAase, phosphotransacetylase, papain, ovalbumin, bovine serum albumin (BSA), protamine sulfate, and polylysine. The absorbance spectrum of porphyrins is different for native compared with heat denatured RNAase. A unique absorbance wavelength red shift is observed with trypsin when trypsin inhibitor is present, indicating that porphyrins incorporated with proteins can detect conformational changes in the protein. The absorbance spectrum of the Soret band of TPPS undergoes bathochromic shifts upon addition of local anesthetics to acetylcholine esterase (AChE), suggesting that the absorbance spectrum of porphyrins can be used as a reporter of the presence of inhibitors of AChE by indicating conformational changes on binding of the inhibitor.
authors.affiliation: Department of Microbiology and Molecular Genetics, Oklahoma State University, 306 LSE, Stillwater, OK 74078, USA. jharmon@okstate.edu
authors.forename: H J
authors.initials: HJ
authors.lastname: Harmon
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis* / Q000737:chemistry*; D000779:Anesthetics, Local / Q000032:analysis / Q000737:chemistry; D015374:Biosensing Techniques; D002800:Cholinesterase Inhibitors / Q000032:analysis* / Q000737:chemistry*; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D009943:Organophosphorus Compounds / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology; D011166:Porphyrins / Q000737:chemistry / Q000494:pharmacology; D011487:Protein Conformation / Q000187:drug effects; D011489:Protein Denaturation; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry / Q000379:methods
chemical_list: D000779:Anesthetics, Local; D002800:Cholinesterase Inhibitors; D046911:Macromolecular Substances; D009943:Organophosphorus Compounds; D011166:Porphyrins; C016136:tetraphenylporphine sulfonate; D000110:Acetylcholinesterase