Bermúdez R, Dagger F, D'Aquino JA, Benaim G, Dawidowicz K. Characterization of mitochondrial electron-transfer in Leishmania mexicana.
Mol Biochem Parasitol 1997;
90:43-54. [PMID:
9497031 DOI:
10.1016/s0166-6851(97)00131-x]
[Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Some general features of the respiratory chain and respiratory control were characterized in coupled mitochondrial preparations from Leishmania mexicana promastigotes. O2 uptake was sensitive to the electron-transfer inhibitors rotenone, flavone, malonate, 4,4,4-trifluoro-1-(2-thienyl) 1.3 butanedione (TTFA), antimycin A, 2n-nonyl-4-hydroxyquinoline-N-oxide (HQNO), myxothiazol, cyanide and azide. A high concentration of rotenone (60 microM) was required to inhibit O2 uptake effectively. Difference spectra revealed the presence of cytochromes (a + a3), b and c. Respiratory control was stimulated 2-fold by ADP with different exogenous oxidizable substrates. Calculated ADP/O ratios were consistent with the notion that ascorbate/N,N,N',N'-tetramethylphenylenediamine (TMPD)-linked and FAD-linked respiration proceeds, respectively, with one third and two thirds of the ATP producing capacity of NADH-linked respiration. State 3 was suppressed by the ATP synthase inhibitors oligomycin and aurovertin and by the adenine nucleotide translocator inhibitors atractyloside and carboxy atractyloside. The protonophore carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) provoked state 3u respiration. The mitochondrial preparation was capable of Ca2+ uptake and Ca2+ stimulated respiration. Data obtained suggests strongly that mitochondrial complexes I, II, III and IV are present in a major pathway of electron-transfer and that oxidative phosphorylation might proceed with high bioenergetic efficiency.
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