Microsomal Hemoproteins in Trypanosoma cruzi

Boiso, J. F. de; Stoppani, A. O. M.

doi:10.3181/00379727-136-35230

Cited by 12 publications

(1 citation statement)

References 5 publications

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“…Although these fractions are far from possessing the purity of those obtained from mammalian tissues, they are fairly well characterized. Mitochondrial fractions from T. cruzi show NADH oxidase, NADH dehydrogenase and succinate dehydrogenase activities, and contain a cytochrome system with cytochromes a + a3, b and C558 (Boiso & Stoppani, 1971; Agosin et al, 1976;Docampo et al, 1978b). Microsomal fractions show an antimycin-insensitive NADH-cytochrome c reductase activity and contain cytochrome P-450 (Boiso & Stoppani, 1971; Agosin et al, 1976).…”

Section: Resultsmentioning

confidence: 99%

Effect of β-lapachone on superoxide anion and hydrogen peroxide production in Trypanosoma cruzi

Boveris¹,

Docampo²,

Turrens³

et al. 1978

Biochemical Journal

112

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Addition of beta-lapachone, an o-naphthoquinone endowed with trypanocidal properties to respiring Trypanosoma cruzi epimastigotes induced the release of O2- and H2O2 from the whole cells to the suspending medium. The same beta-lapachone concentration (4 micron) that released H2O2 at maximal rate completely inhibited T. cruzi growth in a liquid medium. The position isomer, alpha-lapachone, did not stimulate O2- and H2O2 release, and did not inhibit epimastigote growth. beta-Lapachone was able to stimulate H2O2 production by the epimastigote homogenate in the presence of NADH as reductant. The same effect was observed with the mitochondrial fraction supplemented with NADH, where beta-lapachone enhanced the generation of O2- and H2O2 4.5- and 2.5-fold respectively. beta-Lapachone also increased O2- and H2O2 production (2.5 and 2-fold respectively) by the microsomal fraction with NADPH as reductant. Cyanide-insensitive NADH and NADPH oxidation by the mitochondrial and microsomal fractions (quinone reductase activity) was stimulated to about the same extent by beta-lapachone. alpha-Lapachone was unable to increase O2- and H2O2 production and quinone reductase activity of the mitochondrial and microsomal fractions.

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Section: Resultsmentioning

confidence: 99%

Effect of β-lapachone on superoxide anion and hydrogen peroxide production in Trypanosoma cruzi

Boveris¹,

Docampo²,

Turrens³

et al. 1978

Biochemical Journal

112

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Hydrogen peroxide generation inTrypanosoma cruzi

Boveris

Stoppani

1977

Experientia

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Homogenates from T. cruzi epimastigotes produced 3.4 pmoles H2O2/min 10(6) cells, as detected by the cytochrome c peroxidase assay. Addition of NADH or NADPH increased H2O2 production by a factor of 3 and 5, respectively. When supplemented with NADH and NADPH, the mitochondrial, microsomal and supernatant fractions produced H2O2, the soluble fraction and the mitochondrial membranes being apparently the main generators of H2O2. The epimastigote homogenates showed cyanide-sensitive superoxide dismutase activity, equivalent to 0.28 microgram bovine superoxide dismutase per mg homogenate protein.

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