UNT Libraries - 12 Matching Results

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N-Acylethanolamines and Plant Phospholipase D

Description: Recently, three distinct isoforms of phospholipase D (PLD) were identified in Arabidopsis thaliana. PLD α represents the well-known form found in plants, while PLD β and γ have been only recently discovered (Pappan et al., 1997b; Qin et al., 1997). These isoforms differ in substrate selectivity and cofactors required for activity. Here, I report that PLD β and γ isoforms were active toward N-acylphosphatidylethanolamine (NAPE), but PLD α was not. The ability of PLD β and γ to hydrolyze NAPE mar… more
Date: December 1998
Creator: Brown, Shea Austin
Item Type: Refine your search to only Thesis or Dissertation
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Chemical Mechanism of the Catalytic Subunit of Camp-Dependent Protein Kinase: Methods for Determining the Primary ¹⁸O Isotope Effects Using the Remote Label Technique

Description: A description of the nature of the transition state structure for phosphoryl transfer in the cAPK reaction requires a measurement of the primary 180 isotope effect at the serine hydroxyl acceptor. Since it is difficult to obtain primary 180 isotope effect directly, the 15N/1 4N ratio of the a-amine of the C-terminal glycine in the peptide Leu Arg-Lys-Ala-Ser-Leu-Gly (when serine is phosphorylated) was used to represent on the phosphorylation at serine. 15N Glycine, ' 4N-Glycine and 180 serine w… more
Date: December 1991
Creator: Chen, Gang, 1963-
Item Type: Refine your search to only Thesis or Dissertation
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Evidence for the Interaction of GTP with Rat Liver Glyoxalase II

Description: Glyoxalase 11, the second enzyme of the glyoxalase system, hydrolyzes S-D-lactoylglutathione (SLG) to regenerate glutathione (GSH) and liberate free D-lactate. It was found that GTP binds with Gil from rat liver and inhibits Gil activity. Preincubation experiments showed that the binding is relatively tight, since more than 15 minutes are required to release GTP from the complex following dilution. Inhibition kinetics studies indicate that GTP is a "partially competitive inhibitor"; Thus, it wo… more
Date: December 1991
Creator: Yuan, Win-Jae
Item Type: Refine your search to only Thesis or Dissertation
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Homologous Recombination in Q-Beta Rna Bacteriophage

Description: Q-Beta phage RNAs with inactivating insertion (8 base) or deletion (17 base) mutations within their replicase genes were transfected into Escherichia coli spheroplasts containing QB replicase provided in trans by a resident plasmid. Replicase-defective (Rep~) Q3 phage produced by these spheroplasts were unable to form plaques on cells lacking this plasmid. When individual Rep~ phage were isolated and grown to high titer in cells containing plasmid derived Q3 replicase, revertant Q3 phage (Rep')… more
Date: May 1992
Creator: Palasingam, Kampan
Item Type: Refine your search to only Thesis or Dissertation
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Mechanism of Activation by Autophosphorylation of an S6/H4 Kinase Isolated From Human Placenta

Description: A novel molecular mechanism of autophosphorylation-dependent activation of the ser/thr S6/H4 kinase isolated from human placenta is described. Phosphopeptide mapping of the enzyme was used to determine the rate and extent of site-specific autophosphorylation. These data were correlated to phosphotransferase activity of the protein kinase. The results indicated that a sequential phosphorylation of two sites in the catalytic domain is required for maximum activation. Kinetic analysis determined t… more
Date: December 1994
Creator: Benner, Gretchen E. (Gretchen Evonne)
Item Type: Refine your search to only Thesis or Dissertation
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Pre-Steady State Kinetics of the NAD-Malic Enzyme from Ascaris suum in the Direction of Oxidative Decarboxylation of L-Malate

Description: Stopped-flow experiments in which the NAD-malic enzyme was preincubated with different reactants at near saturating substrate concentrations suggest a slow isomerization of the E:NAD:Mg complex. The lag is eliminated by preincubation with Mg˙² and malate suggesting that the formation of E:Mg:Malate either bypasses or speeds up the slow isomerization step. Circular dichroic spectral studies of the secondary structural changes of the native enzyme in the presence and absence of substrates support… more
Date: December 1991
Creator: Rajapaksa, Ranjani, 1949-
Item Type: Refine your search to only Thesis or Dissertation
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Protein Kinase C Activation in Hyperglycemic Bovine Lens Epithelial Cells

Description: This study demonstrates the presence of protein kinase C activity in both cytosolic and membrane fractions of bovine lens epithelial cells in culture. Protein kinase C activity is similar in normal and hyperglycemic cells. Furthermore, the ability of the enzyme to translocate from the cytosol to the membrane following phorbol ester treatment is unimpeded by hyperglycemic conditions. Moreover, protein kinase C activation had no effect on myoinositol uptake either in normal cells or in cells expo… more
Date: December 1993
Creator: Fan, Wen-Lin
Item Type: Refine your search to only Thesis or Dissertation
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Regulation of an S6/H4 Kinase in Crude Lymphosarcoma P1798 Preparations

Description: Purified S6/H4 kinase (Mr 60,000) requires autophosphorylation for activation. A rabbit anti-S6/H4 kinase peptide (SVIDPVPAPVGDSHVDGAAK) antibody recognized both the S6/H4 kinase holoenzyme and catalytic domain. Immunoreactivity with p60 kinase protein, and S6/H4 kinase activity were precisely correlated in fractions obtained from ion exchange chromatography of P1798 lymphosarcoma extracts. An enzyme which catalyzed the MgATP-dependent phosphorylation and activation of S6/H4 kinase coeluted wit… more
Date: December 1998
Creator: Taylor, Allison Antoinette
Item Type: Refine your search to only Thesis or Dissertation
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Sensitive Microtiter Assays for NAD, NADP and Protein Quantification in Human Lymphocytes

Description: Intracellular levels of NAD are of renewed interest in clinical and basic science research due to the new discovery of enzymes which utilize NAD as a substrate. Microtiter assays for the determination of NAD, NADP and protein were developed as modifications of previously published methods. The resulting assays are simple, cost effective and sensitive. An improved method of isolating lymphocytes was also developed. The resultant procedure requires one hour and removes greater than 99.9% of the p… more
Date: May 1990
Creator: Johnson, James, 1964-
Item Type: Refine your search to only Thesis or Dissertation
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Studies on ADP-Ribose Polymer Metabolism in Cultured Mammalian Cells Following DNA Damage

Description: ADP-ribose polymer metabolism has been studied in human cells derived from a patient with Glutamyl Ribose Phosphate Storage Disease (GRPSD) and in mouse C3H1OT1/2 cells following oxidative stress induced by hydrogen peroxide (H202 ). It has been postulated that GRPSD resulted from an abnormality in ADP-ribose polymer metabolism. This study has shown that these cells exhibit reduced poly(ADP ribose) polymerase activity which is proposed to result from modification of the enzyme with ribose phosp… more
Date: May 1991
Creator: Maharaj, Geeta
Item Type: Refine your search to only Thesis or Dissertation
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Studies on Poly (ADP-ribose) Synthesis in Lymphocytes of Systemic Lupus Erythematosus Patients

Description: A method for assaying poly (ADP-ribose) polymerase (PADPRP) activity in lymphocytes of systemic lupus erythematosus (SLE) patients has been developed. Using this method, PADPRP activity has been studied in lymphocytes from 15 patients and 13 controls. The mean activity in SLE lymphocytes was significantly lower than that in controls and 60% of the SLE patients demonstrated activities below the minimum of the control population. Possible mechanisms for this altered metabolism were investigated. … more
Date: December 1991
Creator: Chen, Hai-Ying
Item Type: Refine your search to only Thesis or Dissertation
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Synthesis and Kinetic Mechanism Study of Phosphonopeptide as a Dead-End Inhibitor of cAMP-Dependent Protein Kinase

Description: DL-2-Amino-4-phosphonobutyric acid, an isostere of phosphoserine, was incorporated into the heptapeptide sequence, Leu-Arg-Arg-Ala-(DL-2-amino-4-phosphonobutyric acid)-Leu-Gly, for kinetic mechanistic studies of the cAMP-dependent protein kinase. To block the phosphono hydroxyl groups, methyl, ethyl and 4nitrobenzyl esters were studied as possible protecting groups. The phosphono diethyl ester of the N-Fmoc-protected amino acid was utilized in the synthesis of the heptapeptide. Two configuratio… more
Date: December 1991
Creator: Yang, Chunhua
Item Type: Refine your search to only Thesis or Dissertation
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