Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Quantitative determination of cardiolipin from two mitochondrial electron-transferring complexes was achieved using a rapid and sensitive silicic acid HPLC method combined with digital analysis of the elution profile. Phospholipid samples containing as little as 0. 01 nmol of cardiolipin were accurately analyzed. Phospholipids from detergent-solubilized cytochrome bc1 (EC 1.10.2.2) and cytochrome c oxidase (EC 1.9.3.1) were extracted by an organic two-phase system and analyzed by isocratic normal-phase HPLC after dissolving the dried sample in the mobile phase (cyclohexane:2-propanol:5 mM phosphoric acid, 50:50:2.9, v/v/v). Analysis was performed by the method of standard addition in which increasing amounts of cardiolipin (0 to 5 nmol) are added to a constant amount of phospholipid extract containing an unknown amount of cardiolipin. By determining the slope and intercept of a plot of the HPLC elution peak area as a function of the amount of standard cardiolipin added, the amount of cardiolipin in the unknown is determined. By this analysis, purified, detergent-solubilized bovine heart cytochrome bc1 and cytochrome c oxidase contained 9.2 +/- 0.7 and 3.05 +/- 0.05 mol cardiolipin per mole of enzyme, respectively. The method was also used to prove that cardiolipin could be completely removed from each complex by digestion with Crotalus atrox phospholipase A2, i.e., each delipidated complex contained less than 0.05 mol cardiolipin per mole of complex. The rapidity and high sensitivity of this method make it very useful for analysis of cardiolipin in other biological samples.
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PMID:Quantitative determination of cardiolipin in mitochondrial electron transferring complexes by silicic acid high-performance liquid chromatography. 991 73

The role of nitrate reduction to produce nitric oxide (NO) and its subsequent oxidation by oxyhaemoglobin as a mechanism to maintain plant cell energetics during hypoxia is examined. Nitrate reduction in hypoxic conditions can be considered as an alternative respiratory pathway, with nitrate as an intermediate electron acceptor, contributing to the oxidation of NADH. NO, produced in the reaction, does not accumulate due to the induction of hypoxia-induced (class 1) haemoglobins. These haemoglobins remain in the oxyhaemoglobin form, even at oxygen tensions two orders of magnitude lower than necessary to saturate cytochrome c oxidase. They act, probably in conjunction with a flavoprotein, as NO dioxygenases converting NO back to nitrate, consuming NAD(P)H in the process. The overall system oxidizes 2.5 moles of NADH per one mole of nitrate recycled during the reaction, leading to the maintenance of redox and energy status during hypoxia and resulting in the reduced production of ethanol and lactic acid.
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PMID:Nitrate, NO and haemoglobin in plant adaptation to hypoxia: an alternative to classic fermentation pathways. 1544 80


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