objective(s) phosphatidate phosphohydrolase (pap) catalyzes the dephosphorylation of phosphatidic acid to yield pi and  diacylglycerol. two different forms of pap in rat hepatocyte have been reported. pap1 is located in cytosolic and microsomal fractions and participates in the synthesis of triacylglycerols, phosphatidylcholine, and phosphatidylethanolamine, whereas the other form of phosphatid...

The ACCO gene from Lycopersicon esculentum (tomato) has been cloned into the expression vector PT7-7. The highly expressed protein was recovered in the form of inclusion bodies. ACCO is inactivated by diethyl pyrocarbonate (DEPC) with a second-order rate constant of 170 M min. The pH-inactivation rate data imply the involvement of an amino acid residue with a pK value of 6.05. The difference UV...

Ehrenwörtliche Versicherung Diese Dissertation wurde selbständig, ohne unerlaubte Hilfe erarbeitet. I Abbreviations µM micromolar APS ammoniumperoxodisulfate BSA bovine serum albumin cDNA copy DNA cpm counts per minute C-terminal carboxyterminal dATP desoxyadenosintriphosphate dCTP desoxycytosintriphosphate DEPC diethylpyrocarbonate DNA desoxyribonucleicacid dNTP desoxynucleosidtriphosphate DTT...

Effects of several chemical probes selectively modifying various amino-acid residues on the activity of UDP-glucose : solasodine glucosyltransferase from eggplant leaves was studied. It was shown that diethylpyrocarbonate (DEPC), a specific modifier of histidine residues, was strongly inhibitory. However, in the presence of excessive amounts of the enzyme substrates, i.e. either UDP-glucose or ...

Free transition metal ions oxidize lipids and lipoproteins in vitro; however, recent evidence suggests that free metal ion-independent mechanisms are more likely in vivo. We have shown previously that human ceruloplasmin (Cp), a serum protein containing seven Cu atoms, induces low density lipoprotein oxidation in vitro and that the activity depends on the presence of a single, chelatable Cu ato...

The albA gene from Klebsiella oxytoca encodes a protein that binds albicidin phytotoxins and antibiotics with high affinity. Previously, it has been shown that shifting pH from 6 to 4 reduces binding activity of AlbA by about 30%, indicating that histidine residues might be involved in substrate binding. In this study, molecular analysis of the albA coding region revealed sequence discrepancies...

Activity of the AE2/SLC4A2 anion exchanger is modulated acutely by pH, influencing the transporter's role in regulation of intracellular pH (pH(i)) and epithelial solute transport. In Xenopus oocytes, heterologous AE2-mediated Cl(-)/Cl(-) and Cl(-)/HCO(3)(-) exchange are inhibited by acid pH(i) or extracellular pH (pH(o)). We have investigated the importance to pH sensitivity of the eight histi...

Four 25-nt long oligonucleotides containing dA and dT (D1, D2, D3, and D4) which are capable of forming parallel-stranded (ps) or antiparallel-stranded (aps) duplexes have been synthesized [Rippe, K., Ramsing, N. B., & Jovin, T. M. (1989) Biochemistry 28, 9536-9541]. In the present study, the OsO4-pyridine complex (Os,py), diethyl pyrocarbonate (DEPC), KMnO4, and the 1,10-phenanthroline-cuprous...

The human UDP-glucuronosyltransferase isoform UGT1A6 catalyzes the nucleophilic attack of phenolic xenobiotics on glucuronic acid, leading to the formation of water-soluble glucuronides. Based on the irreversible inhibition of the enzyme activity by the histidyl-selective reagent diethyl pyrocarbonate (DEPC), histidine was suggested to play a key role in the glucuronidation reaction. Therefore,...