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Synthesis of deoxyhypusine in eukaryotic initiation factor 4D in rat hepatoma cells.Murphey, Roberta Jean. January 1989 (has links)
The aim of this research was to study the mechanism involved in the synthesis of deoxyhypusine, the intermediate step in the synthesis of the amino acid hypusine. Oeoxyhypusine is derived from the butylamine moiety of a spermidine molecule which is added to the famino group of one lysine in the eukaryotic initiation factor 40 (eIF-4D). Initially, a hepatoma tissue cell (HTC) lysate with a pH of 9.5 in glycine buffer and with a depleted spermidine pool supported deoxyhypusine synthesis in protein. Since CHES buffer was as efficient as glycine buffer, the synthesis of deoxyhypusine was pH dependent (optimum ∼9.2) and not buffer dependent. Next, several inhibitors were used in the cell-free system to block deoxyhypusine synthesis. Only guazatine, a plant amine oxidase inhibitor, completely inhibited deoxyhypusine synthesis. This suggested that an oxidase was involved in deoxyhypusine synthesis. In addition factors were investigated as possible allosteric stimulators of deoxyhypusine formation. NAD⁺, NADH, FAD⁺, FMN⁺, and as nicotinamide were tested for effects on deoxyhypusine formation. NAD⁺ was the most efficient stimulator, but NAOH and nicotinamide also stimulated deoxyhypusine formation. Although these factors increased the synthesis of deoxyhypusine, these assays were done in buffer with low concentrations of spermidine. When the spermidine pool was replenished, these effects were diminished. Thus, it appeared that NAD⁺ may lower the apparent K(m) for spermidine without affecting the V(max) of deoxyhypusine synthesis. The inhibition of deoxyhypusine synthesis by guazatine implied the involvement of a polyamine oxidase. Therefore, the effect of oxygen depletion on deoxyhypusine formation was investigated. The depletion of oxygen reduced the level of deoxyhypusine synthesis to 12% of the control. This activity could be restored to 85% by reoxygenation of the lysate. Thus in support of the suggestion made by the guazatine data, a spermidine oxidase in involved in deoxyhypusine formation. The most significant contribution of this work was the development of a cell free system to study deoxyhypusine. This synthesis required an unusually high pH in vitro and required polyamine depletion (Chapter 2). In addition, synthesis requires a unique spermidine oxidase that is blocked by a guazatine and is conditionally stimulated by NAD⁺ (Chapter 3).
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Zirconium- and titanium-mediated syntheses of (-)-α-kainic acid and related studiesCampbell, Andrew Duncan January 2000 (has links)
No description available.
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Determinants of growth in the early mouse embryoLamb, Victoria Kay January 1996 (has links)
No description available.
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The neuroprotective effects of remacide hydrochloride in patients undergoing elective coronary artery bypass surgeryArrowsmith, Joseph Edmund January 2001 (has links)
No description available.
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Identification and characterisation of a novel form of PKC-zetaRao, Sudha January 1999 (has links)
No description available.
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Synthetic studies related to chirally-labelled amino-acidsAugust, R. A. January 1987 (has links)
No description available.
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Genetic and biochemical studies of D-amino acid dehydrogenase of Pseudomonas aeruginosaMagor, A. M. January 1985 (has links)
No description available.
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The electrochemical nitration of proteins and protein model systemsCampbell, Colin James January 1997 (has links)
No description available.
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Asymmetric synthesis of cyclic aminesSmethurst, Chris January 1998 (has links)
No description available.
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Synthetic studies related to natural productsMalhi, B. S. January 1988 (has links)
No description available.
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