Lipoxygenase activities of human platelets and their subcellular fractions: Comparison between lipoxygenase-deficient platelets and normal platelets

Kanaji, Kenji; Okuma, Minoru; Ushikubi, Fumitaka; Uchino, Haruto

doi:10.1016/0952-3278(88)90112-3

Cited by 3 publications

(2 citation statements)

References 19 publications

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“…Anticoagulation of blood and preparation of washed platelets were performed as described previously (4). Washed platelets (1.0 X 10 9 /ml) were resuspended in sonication buffer (50 mM Tris-HCI, pH 7.4, 5 mM EDTA, I mM phenylmethylsulfonyl fluoride, 20 J.Lg of leupeptin!ml of phosphate-buffered saline), disrupted by sonication (8), and centrifuged for 12 min at 12,000 g and 4° C. The supernatant (homogenate) was carefully collected and further centrifuged for 60 min at 105,000 g and 4° C. The supernatant (cytosol fraction) was •removed, while the pellet (microsomal fraction) was gently rinsed twice with 300 mM sucrose and suspended in the sucrose solution of equal volume to the supernatant.…”

Section: Platelet Preparation and Their Subcellular Fractionationmentioning

confidence: 99%

“…The reaction products were extracted with 2 ml of diethyl ether. After evaporation of the organic solvent, reversed-phase high-performance liquid chromatography (RP-HPLC) and quantification of the reaction products were carried out as described previously (8). For the measurement of the enzyme activities of immunoprecipitates, the anti-12-LOX-immunoprecipitates prepared from 1.0 X 10 9 platelets as descried above were washed twice with sonication buffer, and finally resuspended in the sonication buffer.…”

Section: Arachidonate Metabolismmentioning

confidence: 99%

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Qualitative Platelet 12-Lipoxygenase Abnormality in a Patient with Essential Thrombocythemia

et al. 1997

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SummaryQuantitative platelet 12-lipoxygenase (12-LOX) deficiency has been reported in some patients with myeloproliferative disorders (MPD). We report here for the first time a novel qualitative abnormality of the 12-LOX enzyme of platelets from a patient with essential thrombocythemia. The anti-12-LOX immunoprecipitates from the patient’s platelet homogenates showed a deficiency of 12-LOX activity, but contained normal amount of 12-LOX protein. There was no difference in subcellular localization of the enzyme between the patient’s platelets and normal ones. This 12-LOX protein lacking its enzyme activity showed slightly larger electrophoretic mobility than normal one, suggesting a molecular abnormality of the enzyme. However, we could not detect any genetic mutation causing such abnormalities in all exons of 12-LOX gene by sequencing the patient’s PCR-amplified DNA. Thus, our results indicate that the deficient activity of this abnormal 12-LOX protein is probably due to a posttranslational modification, and the possibility that platelets of some MPD patients have qualitative abnormality of the 12-LOX enzyme besides quantitative one.

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Section: Platelet Preparation and Their Subcellular Fractionationmentioning

confidence: 99%

Section: Arachidonate Metabolismmentioning

confidence: 99%

Qualitative Platelet 12-Lipoxygenase Abnormality in a Patient with Essential Thrombocythemia

et al. 1997

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Anti-platelet action of isoliquiritigenin, an aldose reductase inhibitor in licorice

Tawata

Aida

Noguchi

et al. 1992

European Journal of Pharmacology

107

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Deficient lipoxin synthesis: a novel platelet dysfunction in myeloproliferative disorders with special reference to blastic crisis of chronic myelogenous leukemia

Stenke

Edenius

Samuelsson

et al. 1991

Blood

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The capacity to convert exogenous leukotriene A4 to lipoxins (LXs) was investigated in platelet suspensions from patients with myeloproliferative disorders (MPD) (n = 22) and healthy control subjects (n = 14). Platelets isolated from the controls produced mainly LXA4, but also 6(S)-LXA4 and the all-trans isomers of lipoxins A4 and B4, as determined by high-performance liquid chromatography and computerized UV spectroscopy. In comparison to control levels, the mean LX synthesis was significantly lower in platelets from the MPD patients (438.7 +/- 62.8 and 157.4 +/- 31.2 pmol LXA4 per 10(9) platelets, respectively; mean +/- SEM; P = .0001). Platelets from six of the patients showed a particularly low capacity to produce LXs, resulting in LX levels below the detection limit or less than 7% of mean control levels. Notably, all these patients were in blastic crisis of chronic myelogenous leukemia (CML). This severely deficient LX production was paralleled by a dramatically attenuated conversion of arachidonic acid to 12-HETE (12-hydroxyheptadecatrienoic acid), a product formed via the prostaglandin endoperoxide synthase pathway, was normal. In addition, longitudinal studies of CML patients showed that blastic metamorphosis was associated with a markedly reduced capability to synthesize LXs, while this capacity improved after retransformation into a second chronic phase. The results reveal deficient LX synthesis as a novel platelet dysfunction in MPD, particularly in blastic crisis of CML in which an essentially abolished 12-lipoxygenase activity may be a general phenomenon.

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Lipoxygenase activities of human platelets and their subcellular fractions: Comparison between lipoxygenase-deficient platelets and normal platelets

Cited by 3 publications

References 19 publications

Qualitative Platelet 12-Lipoxygenase Abnormality in a Patient with Essential Thrombocythemia

Qualitative Platelet 12-Lipoxygenase Abnormality in a Patient with Essential Thrombocythemia

Anti-platelet action of isoliquiritigenin, an aldose reductase inhibitor in licorice

Deficient lipoxin synthesis: a novel platelet dysfunction in myeloproliferative disorders with special reference to blastic crisis of chronic myelogenous leukemia

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