Preparation and characterization of Mn-salophen complex with superoxide scavenging activity.
Mn(III)-salophen complex with superoxide scavenging activity was prepared from manganese(III) acetate dihydrate and salophen in ethanol. Visible absorption spectrum of the red-brown complex exhibits a shoulder at 430 nm which was absent with either salophen or manganic acetate alone. Titration of salophen with manganese(III) is consistent with a 1:1 Mn to salophen stoichiometry of the complex based on changes in the absorbance at 500 nm or of superoxide scavenging activity. The superoxide dismutase (SOD)-like activity of the complex in the xanthine-xanthine oxidase/cytochrome c assay was 1450 units/mg salophen. The SOD activity of the complex was suppressed 50% in the presence of EDTA (1 mM), but was not altered in the presence of bovine serum albumin (1 mg/ml) or crude protein extract of Escherichia coli QC779 sodA-sodB- (1 mg/ml). E. coli QC779 sodA-sodB- grew scantily after an 8-h lag phase in aerobic M63 glucose minimal medium. The aerobic growth of the E. coli SOD double mutant in glucose minimal medium was greatly enhanced in the presence of 5 or 10 microM Mn-salophen complex compared to that of control after 24 h incubation. Mn-desferal green complex (10 microM) and pink complex (5 microM) also increased growth rate of E. coli QC779 sodA-sodB- but to a lesser extent than Mn-salophen complex. However, the growth was completely inhibited by 50 microM Mn-salophen complex, 100 microM Mn-desferal green complex, or 10 microM Mn-desferal pink complex.
Department of Biochemistry and Anaerobic Microbiology, Virginia Polytechnic Institute, Blacksburg 24061-0308.
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D000332:Aerobiosis; D003676:Deferoxamine / Q000031:analogs & derivatives; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D008345:Manganese / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry / Q000494:pharmacology*; D012459:Salicylates / Q000737:chemistry / Q000494:pharmacology; D013053:Spectrophotometry; D013482:Superoxide Dismutase / Q000235:genetics; D013481:Superoxides / Q000378:metabolism*
D016166:Free Radical Scavengers; D009942:Organometallic Compounds; D012459:Salicylates; D013481:Superoxides; C090416:salophen; C068338:manganese desferioxamine; D008345:Manganese; D013482:Superoxide Dismutase; D003676:Deferoxamine