Tritrichomonas foetus and Trichomonas vaginalis: the pattern of inactivation of hydrogenase activity by oxygen and activities of catalase and ascorbate peroxidase.
The concentration-dependence of the inhibition of whole-cell hydrogen formation by oxygen has been measured in the trichomonads Trichomonas vaginalis and Tritrichomonas foetus, and compared with the oxygen inhibition of the in situ hydrogenase activity as measured by a tritium exchange assay. The inhibition profiles closely paralleled each other, suggesting that hydrogenase is the primary site of inhibition of anaerobic fermentative metabolism. In addition the inhibition profile for isolated hydrogenosomes was measured and shown to be similar to that for whole organisms. Ascorbate peroxidase was shown to be present in both organisms whereas catalase was confirmed to be present only in Tritr. foetus. The kinetic parameters of both enzymes were measured and their respective roles in oxygen protection discussed.
Page-Sharp
Madhu
M
Division of Biochemistry and Molecular Biology, School of Life Sciences, Faculty of Science, The Australian National University, Canberra, ACT 0200, Australia.
Behm
Carolyn A
CA
Division of Biochemistry and Molecular Biology, School of Life Sciences, Faculty of Science, The Australian National University, Canberra, ACT 0200, Australia.
Smith
Geoffrey D
GD
Division of Biochemistry and Molecular Biology, School of Life Sciences, Faculty of Science, The Australian National University, Canberra, ACT 0200, Australia.
D000818:Animals; D060387:Ascorbate Peroxidases; D002374:Catalase / Q000032:analysis; D006859:Hydrogen / Q000378:metabolism; D006864:Hydrogenase / Q000187:drug effects*; D010100:Oxygen / Q000494:pharmacology*; D010544:Peroxidases / Q000032:analysis*; D014246:Trichomonas vaginalis / Q000201:enzymology*; D016835:Tritrichomonas foetus / Q000201:enzymology*
D006859:Hydrogen; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D006864:Hydrogenase; D010100:Oxygen