Respiratory chain enzyme activities with different substrates. PS – Phytomonas serpens, TB(PF) – Trypanosoma brucei (procyclic form), TB(BF) – Trypanosoma brucei (blood stream form), LT – Leishmania tarentolae. The unit (U) of appropriate activity is defined as an amount of enzyme required for conversion of: 1 nMol of NADH/min for NADH dehydrogenase; 1 nMol of 2,6-dichlorophenolindophenol/min for succinate dehydrogenase; 1 μMol of cytochrome c for cytochrome c reductase and 1 nMol of appropriate coenzyme Q/min for TAO. Presented data are an average of at least three independent biological experiments, each measured in triplicate. Only trypanosomatids with measurable corresponding activity in their mitochondria are shown.