title: Evidence for the presence of two terminal oxidases in the trypanosomatid Crithidia oncopelti.
abstract: Increasing concentrations of cyanide inhibited the respiration of whole cells of Crithidia oncopelti in a biphasic fashion. Approximately 80% inhibition was attained with 40 microM-KCN. No further inhibition occurred until the concentration of KCN reached approximately 200 microM. Thereafter inhibition rose gradually to 100% at 1500 microM-KCN. Difference spectra revealed the presence of two CO-reacting haemoproteins. These were shown to be two different functional oxidases by photochemical action spectra obtained by using laser light. One oxidase was identified as cytochrome a + a3 whilst the other had the properties of cytochrome o. Both oxidases could be detected in cells at all stages of growth by the above methods.
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000494:pharmacology; D003421:Crithidia / Q000187:drug effects / Q000201:enzymology*; D017936:Cytochrome a Group; D003573:Cytochrome b Group; D003580:Cytochromes; D003576:Electron Transport Complex IV / Q000032:analysis*; D029968:Escherichia coli Proteins; D007834:Lasers; D010101:Oxygen Consumption / Q000187:drug effects; D010777:Photochemistry; D011190:Potassium Cyanide / Q000494:pharmacology; D013053:Spectrophotometry; D013696:Temperature
chemical_list: D017936:Cytochrome a Group; D003573:Cytochrome b Group; D003580:Cytochromes; D029968:Escherichia coli Proteins; D002248:Carbon Monoxide; C017168:cytochrome bo, E coli; D003576:Electron Transport Complex IV; D011190:Potassium Cyanide