Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.5.5 (CPS)
 1,262 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The reversed-phase high-performance liquid chromatography of three synthetic opioid peptides, 5leucine-enkephalin, 5methionine-enkephalin and [D-2alanine]-5methionine enkephalin, has been studied after their pre-column fluorogenic derivatization with naphthalene-2,3-dicarboxaldehyde in the presence of cyanide to the corresponding 1-cyanobenz[f]isoindole (CBI) derivatives. The chromatographic properties of the three synthetic CBI-peptides were characterized using three different stationary phases, ODS Hypersil, CPS Hypersil and Spherisorb Phenyl, eluted with mobile phases containing various concentrations of methanol, tetrahydrofuran or acetonitrile in 26 mM trifluoroacetic acid, adjusted to pH 3.5. The data obtained using single chromatographic columns were used to design a multi-dimensional system in which the three synthetic CBI-peptides of interest were transferred as a single fraction from one column to a second. The first column served to separate the peptides from the majority of the material in the samples, and the second column was used to separate the three CBI-peptides from each other. The best separation was achieved in which the first column was Spherisorb Phenyl and the second column was ODS Hypersil. Both columns were eluted with a mobile phase of 45% acetonitrile (v/v) in 26 mM trifluoroacetic acid (pH 3.5) at a flow-rate of 1.0 ml/min. The method has been applied to the determination of leucine- and methionine-enkephalin-like fluorescence in the striatum of the rat brain.
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PMID:Multi-dimensional high-performance liquid chromatography of opioid peptides following pre-column derivatization with naphthalene-2,3-dicarboxaldehyde in the presence of cyanide ion. Preliminary results on the determination of leucine- and methionine-enkephalin-like fluorescence in the striatum region of the rat brain. 259 17

The 6 enzymes involved in de novo synthesis of pyrimidines were measured in Plasmodium falciparum isolated by saponin lysis from RBC's nonsynchronized and synchronized in vitro cultures. The total activities were found to be dependent on the stage of the P. falciparum cycle. In parasites isolated from synchronized cultures, the highest activities for all enzymes were found at about 27 hr after synchronization in the late trophozoite stage, or just before schizont formation. Merozoites and ring forms contained little de novo activity. The first enzyme of the pathway, carbamyl phosphate synthetase (CPS-II) preferentially utilized glutamine. Ammonia was a poor substrate. CPS-II was unstable in the absence of the cryoprotectants, dimethylsulfoxide and glycerol. The apparent Km for MgATP--was 3.8 +/- 0.7 mM and the enzyme in all morphological forms of P. falciparum (ring, mature trophozoites and schizonts) was inhibited by UTP. The activity of the fourth enzyme of the pathway, dihydroorotate dehydrogenase, appeared to be linked to the cell's respiratory chain; inhibitors of mammalian electron transport such as cyanide, amytal, antimycin A, thenoyltrifluoroacetone and ubiquinone analogs also inhibited the P. falciparum enzyme. The demonstration of the variation of activity of the pyrimidine enzymes correlates with the increased synthesis of nucleic acids in the late trophozoite stage. These observations provide a basis for the testing of the effectiveness of pyrimidine analogs as potential antimetabolites against various forms of the parasite.
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PMID:Pyrimidine de novo synthesis during the life cycle of the intraerythrocytic stage of Plasmodium falciparum. 615 76

Transport of the precursor for carbamoyl-phosphate synthetase I into mitochondria in Reuber hepatoma H-35 cells was inhibited by adding monensin or nigericin to the culture medium at a concentration of 0.5 microM, and the enzyme precursor accumulated, mainly in the cytosolic fraction. Accumulated precursor was degraded slowly with a half-life of more than 16 min. Valinomycin, nonactin, A23187, X-537A (lasalocid), bromo-lasalocid, and carbonyl cyanide m-chlorophenylhydrazone did not exhibit these effects at concentrations at which they did not inhibit protein synthesis of the cells.
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PMID:Monovalent carboxylic ionophores inhibit transport of carbamoyl-phosphate synthetase I into mitochondria in Reuber hepatoma H-35 cells and cause accumulation of enzyme precursor. 669 10