title: Polystyrene microbridges used in sitting-drop crystallization release 1,4-diphenyl-2-butene, a novel inhibitor of human MAO B.
abstract: In the course of protein-structure determinations of the membrane-bound enzyme monoamine oxidase B (MAO B) by X-ray crystallography, a compound was found in the active site of the enzyme that consists of two phenyl rings separated by four C atoms. This compound was identified by chromatography and by mass spectrometry to be 1,4-diphenyl-2-butene and found to be a component of the polystyrene microbridges that are used in protein crystallization. This compound is present at a level of approximately 0.3 mg ( approximately 1.5 micro mol) per microbridge and functions as a competitive inhibitor of MAO B with a K(i) of 35 micro M. The presence of detergents in the crystallization solutions facilitates the extraction of this compound from the polymer medium.
mesh_terms: D000475:Alkenes / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D001713:Biphenyl Compounds / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D003460:Crystallization / Q000379:methods; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D008995:Monoamine Oxidase / Q000737:chemistry* / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D010843:Pichia / Q000378:metabolism; D011137:Polystyrenes / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet; D055672:Static Electricity
chemical_list: D000475:Alkenes; D001713:Biphenyl Compounds; D008996:Monoamine Oxidase Inhibitors; D011137:Polystyrenes; D011994:Recombinant Proteins; D008995:Monoamine Oxidase