Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.25 (triphosphatase)
 1,529 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spiroplasma citri was cultured in three different media that supplied cholesterol and fatty acids from: (i) horse serum, (ii) pleuropneumonia-like organism (PPLO) serum fraction, or (iii) bovine serum albumin-fatty acid-cholesterol. The ability of PPLO serum fraction to support growth varied by lot number. Neither PPLO serum fraction nor the bovine serum albumin medium supported growth as well as the horse serum medium. Analysis of cholesterol, lipid phosphorus, and membrane protein showed the horse serum- and PPLO-grown cells to be indistinguishable, but the bovine serum albumin-grown cells were deficient in lipid phosphorus. The three cultures did not show markedly different fatty acid compositions, but, in all cases, the cultures preferentially incorporated palmitic acid and discriminated against linoleic acid. Cultures grown for different times from logarithmic growth through a degenerative phase showed relatively constant ratios of cholesterol/protein and lipid phosphorus/protein. Fatty acid composition was also relatively constant at the different stages. Adenosine triphosphatase and p-nitrophenyl phosphatase were mainly associated with the membrane, whereas reduced nicotinamide adenine dinucleotide oxidase was either readily removed or not associated with the membrane. The reduced nicotinamide adenine dinucleotide oxidase was inactivated at temperatures above 35 degrees C.
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PMID:Composition and enzyme activities of Spiroplasma citri membranes. 19 32

Mitochondria from brown adipose tissue of cold-acclimated rats (6 degrees C) oxidize alpha-ketoglutarate at a rate twice that of controls (26 degrees C). In both groups, however, the phosphorus: oxygen ratio with alpha-ketoglutarate never exceeded unity, and it is essentially zero with either succinate or alpha-glycerophosphate. Adenosine triphosphatase activity of these mitochondria is very low and it is not stimulated by 2,4-dinitrophenol. In addition, both respiration and phosphorylation are unaffected by adenosine diphosphate, 2,4-dinitrophenol, bovine serum albumin, or glutathione. Endogenous respiration of tissue slices is not stimulated by 2-4-dinitrophenol. It is suggested that brown fat mitochondria are not capable of oxidative phosphorylation, but do phosphorylate at the substrate level. Since these findings provide an unusual example of electron transport by means of an energetically nonconservative pathway, their significance to thermogenesis by brown adipose tissue is particularly emphasized.
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PMID:Nonphosphorylating respiration of mitochondria from brown adipose tissue of rats. 422 65

1. A procedure for the isolation of tightly coupled mitochondria from human early placenta is described. 2. Mitochondria obtained by this method were able to oxidize Krebs cycle intermediates, pyruvate, glutamate, glutamine, palmitoyl-carnitine, alpha-glycerophosphate and beta-hydroxybutyrate. 3. These mitochondria incubated in the medium containing ethylene diamine tetraacetic acid and bovine serum albumin and no added Mg2+ ions exhibited a high respiratory control and adenosine diphosphate:oxygen (ADP:O) ratios corresponding to the theoretical values for all substrates tested. Addition of Mg2+ ions markedly reduced the respiratory control index and ADP:O ratio. 4. Adenosine triphosphatase (ATPase) activity in the obtained mitochondrial preparation was stimulated about tenfold by Mg2+. Oligomycin inhibited Mg2+-stimulated ATPase activity by about 25 per cent, but completely inhibited this activity in the absence of Mg2+ ions. 5. It is concluded that the effect of Mg2+ ions on the respiratory control and ADP:O ratio reported in this paper is exerted mainly through the Mg/+-stimulated oligomycin-insensitive ATPase activity.
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PMID:Tightly coupled mitochondria from human early placenta. 621 76