Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.16.2 (PCP)
 3,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been demonstrated previously that dicarboxylic anions are cotransported during ATP-dependent Ca2+ transport by skeletal muscle sarcoplasmic reticulum (SR) membranes, and that anion cotransport stimulates Ca2+ transport. In the current study, we present evidence that dicarboxylic anion cotransport and Ca2+ transport are kinetically distinct in SR, but both functions are mediated by the CaATPase protein. Preincubation of SR with 40 microM fluorescein isothiocyanate (FITC) (pH 7.0) inhibited essentially all of the Ca2+ ATPase activity, as well as active oxalate-supported and oxalate-independent 45Ca2+ accumulation. The addition of 1 mM beta, gamma-methyleneadenosine 5'-triphosphate (AMP-PCP) to the preincubation media fully protected the dicarboxylic anion-independent Ca2+ ATPase activity and the oxalate-independent active 45Ca2+ accumulation from the inhibitory effects of FITC; however, the ATP-associated [14C]oxalate accumulation, the oxalate-dependent 45Ca2+ accumulation, and the oxalate- and maleate-dependent stimulation of Ca2+ ATPase activity were not protected by AMP-PCP. Thus, the dicarboxylic anion accumulation and the stimulation of Ca2+ uptake by dicarboxylic anions could be functionally separated from the ATP-dependent, anion-independent Ca2+ translocation. FITC bound exclusively to the 100-kDa (CaATPase) and 92-kDa (phosphorylase) proteins in the SR membranes and to purified CaATPase in sodium dodecyl sulfate-polyacrylamide gel electrophoresis; 1 mM AMP-PCP inhibited 50-55% of the FITC fluorescence on the 100-kDa protein, but did not significantly alter fluorescence on the 92-kDa protein. Two-dimensional gel analysis demonstrated a single 100-kDa protein in longitudinal SR membranes. FITC appears to inhibit ATP-dependent Ca2+ transport, and dicarboxylic anion translocation through interaction at separate domains of the CaATPase protein.
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PMID:Inhibition of dicarboxylic anion transport by fluorescein isothiocyanate in skeletal sarcoplasmic reticulum. 171 69

Intracellular ATP-dependent Ca2+-sequestration mechanisms were studied in isolated dispersed rat pancreatic acini following treatment with saponin or digitonin to disrupt their plasma membranes. In the presence of 45Ca2+ concentrations less than 10(-6) mol/liter, addition of 5 mmol/liter ATP caused a rapid increase in 45Ca2+ uptake exceeding the control by fivefold. ADP mimicked the ATP effect by 50 to 60%, whereas other nucleotides such as AMP-PNP, AMP-PCP, CTP, UTP, ITP, GTP, cAMP and cGMP did not. Maximal ATP-promoted Ca2+ uptake was obtained at 10(-5) mol/liter Ca2+. Inhibition of Ca2+ uptake by mitochondrial inhibitors was dependent on the Ca2+ concentration, indicating the presence of different Ca2+ storage systems. Whereas the apparent half-saturation constant found for mitochondrial Ca2+ uptake was approximately 4.5 X 10(-7) mol/liter, in the presence of antimycin and oligomycin (nonmitochondrial uptake) it was approximately 1.4 X 10(-8) mol/liter. In the absence of Mg2+ both ATP- and ADP-promoted Ca2+ uptake was nearly abolished. The Ca2+ ionophore and mersalyl blocked Ca2+ uptake, Electron microscopy showed electron-dense precipitates in the rough endoplasmic reticulum of saponin-treated cells in the presence of Ca2+, oxalate and ATP, which were absent in intact cells and in saponin-cells without ATP or pretreated with A23187. The data suggest the presence of mitochondrial and nonmitochondrial ATP-dependent C2+ storage systems in pancreatic acini. The latter is likely to be located in the rough endoplasmic reticulum.
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PMID:Calcium uptake into acini from rat pancreas: evidence for intracellular ATP-dependent calcium sequestration. 680 Dec 63

The present study was designed to determine the stability of common illicit drugs in stored blood at various time intervals for a period of up to 5 years. The drugs of interest were cocaine and benzoylecgonine, methamphetamine and amphetamine, nonconjugated morphine and codeine, and phencyclidine (PCP). All specimens were from live individuals and were collected in gray-top Vacutainer tubes containing sodium fluoride and potassium oxalate; the tubes were stored at ambient temperature. The results of the study showed that cocaine and benzoylecgonine have poor stability and require quantitative confirmation within a reasonable time period for reliable interpretation. Methamphetamine and PCP were both fairly stable and had a high probability of confirmation upon reanalysis. The stability of nonconjugated morphine showed wide variation throughout the study. Initially, the morphine concentration decreased, then increased at the 3-year interval, and finally decreased at the 4- and 5-year intervals. The significance of the analytical findings are discussed in this report.
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PMID:A 5-year stability study of common illicit drugs in blood. 892 33