title: Photoinactivation of trypanothione reductase and glutathione reductase by Al-phthalocyanine tetrasulfonate and hematoporphyrin.
abstract: The irradiation of Trypanosoma congolense trypanothione reductase (TR), human erythrocyte (HGR) and yeast glutathione reductase (YGR) with visible light in the presence of Al-phthalocyanine tetrasulfonate (A1PcS4) or hematoporphyrine (Hp) caused a time-dependent inactivation of these enzymes. TR was inactivated more rapidly than either HGR or YGR. Half-maximal rates of inactivation were determined in the presence of 100 microM Hp and 1.4-17 microM AlPcS4. The photosensitized irradiation modified the disulfide substrate-binding sites of these enzymes, most likely the conserved catalytic histidine residue. In the dark, AlPcS4 acted as a reversible inhibitor competitive with the disulfide substrate of TR and HGR. These findings suggest the possible use of photosensitized irradiation for preventing the transmission of trypanosomiasis by blood transfusion.
authors.affiliation: Institute of Biochemistry, Vilnius, Lithuania.
authors.forename: R
authors.initials: R
authors.lastname: Kliukiené
authors.forename: A
authors.initials: A
authors.lastname: Maroziené
authors.forename: N
authors.initials: N
authors.lastname: Cénas
authors.forename: K
authors.initials: K
authors.lastname: Becker
authors.forename: J S
authors.initials: JS
authors.lastname: Blanchard
mesh_terms: D000818:Animals; D001771:Blood Banks; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000201:enzymology; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors / Q000737:chemistry*; D006415:Hematoporphyrins / Q000737:chemistry*; D006801:Humans; D007211:Indoles / Q000737:chemistry* / Q000494:pharmacology; D007700:Kinetics; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry* / Q000494:pharmacology; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D014348:Trypanosoma congolense / Q000187:drug effects* / Q000201:enzymology
chemical_list: D004791:Enzyme Inhibitors; D006415:Hematoporphyrins; D007211:Indoles; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; C048577:aluminum tetrasulfophthalocyanine; D009247:NADH, NADPH Oxidoreductases; C049608:trypanothione reductase; D005980:Glutathione Reductase