Search results for " KINASE"

111 Bioluminescence analysis and numerical evaluation of ATP-synthesis by native and reconstituted membranes containing bacterial ATP-synthase

1992

ATP-synthase is a large membrane protein complex, which plays a key role in the energy metabolism of most organisms. It consists of at least eight types of subunits and can be isolated and purified from several organisms, e.g. bacteria. The enzyme couples two reversible reactions: vectorial proton transport through a membrane and synthesis of the energy rich molecule ATP. Both can be investigated with vesicles from native membranes or with reconstituted liposomes from purified ATPsynthase. The analysis is complicated because ATP-synthase catalyzes ATP-synthesis as well as ATP-hydrolysis. Furthermore the ATP level of membrane samples is influenced by adenylate kinase activities of other enzy…

Abstract 1390: A combination of natural polyphenols, a NAD+ booster, and a Toll-like receptor 2/6 agonist exerts high radioprotection in normal tissu…

2021

Abstract Ionizing radiation damages cells via direct ionization of DNA and other cellular targets as well as by indirect effects through reactive oxygen species. The response to radiation exposure depends on the cell type and dose of radiation, inherent tissue sensitivity and repair, and modulating intracellular factors that include cell cycle status, O2 pressure, and levels of thiols and other antioxidants. Potentially protective agents against exposure to harmful radiation have been investigated for decades. However, no ideal radioprotector is currently available. A wide range of phytochemicals are antioxidants and, thus, potentially radioprotective. Topical administration of Pterostilben…

Inhibition of the herpes simplex virus-coded thymidine kinase-complex by 9-?-D-arabinofuranosyladenine 5?-monophosphate (ara-AMP) and 9-(2-hydroxyeth…

1984

The thymidine kinase-complex isolated from herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2) is associated with the following enzyme activities: ATP:dThd (dCyd) deoxypyrimidine kinase, ATP:dTMP thymidylate kinase, ADP:dThd- and AMP:dThd5′-phosphotransferase. In kinetic experiments it is shown that ara-AMP inhibits AMP:dThd- and ADP:dThd phosphotransferase activity, while acyclo-GMP impairs ADP:dThd phosphotransferase reaction only; the inhibition was found to be non-compertitive. The functional subunit ATP:dThd kinase was not affected by either compound.

Isolierung und charakterisierung einer cholinkinase aus Phaseolus vulgaris L.-Keimlingen

1977

Summary The enzyme choline kinase (ATP: Choline phosphotransferase E.C. 2.7.1.32) was extracted and partially purified from hypocotyl hooks of Phaseolus vulgaris L. seedlings. K m -value and pH-dependence of the activity were determined. The amount of enzyme activity in extracts depended on light conditions used for plant growth. Etiolated seedlings showed much lower enzyme levels than those grown in white light. Blue and red light conditions decreased enzyme levels below dark values. The in vitro enzyme activity was influenced by inhibitors and growth regulators. The enzyme activity was stimulated by Atropine, 2-Chloroethylammoniumchloride (Cycocel) and Gibberellic acid and was inhibited b…

Interactions of the mitochondrial membrane rat liver d-3-hydroxybutyrate dehydrogenase with glass beads during adsorption chromatography

1991

D-3-Hydroxybutyrate dehydrogenase (BDH) is an NAD(+)-dependent dehydrogenase of the mitochondrial inner membrane involved in the energetic balance between the liver and peripheral organs in mammals. It allows the conversion of ketone bodies (acetoacetate and D-3-hydroxybutyrate) and it is one of the best documented lipid-requiring enzymes with a dependence on lecithins. After release of proteins from the membrane by phospholipase A2 treatment of salt-treated mitochondria, the rat liver enzyme is absorbed on controlled-pore glass beads. After batch washing, the enzyme, devoid of lipids (apoBDH), is specifically eluted at pH 8.05-8.15 with a 0.1 M Tris-1 M LiBr buffer under reducing condition…

Phosphorylation of cytochrome P450 isoenzymes in intact hepatocytes and its importance for their function in metabolic processes.

1990

Recent data show that besides the well-known long-term regulation of cytochrome P450-dependent monooxygenase activity by induction there also exists a fast regulation by phosphorylation. This phosphorylation occurs when purified cytochromes P450 are combined with purified protein kinases, and also in intact cells. This process is donor- and acceptor-selective leading to phosphorylation of defined isoenzymes by defined protein kinases. This in turn leads to fast and marked changes in metabolism which are selective for given substrates and regio- and stereo-selective for given positions. This in turn is selectively and differentially influenced by the individual control of the protein kinase …

Species-Specific Aggregation Factor In Sponges.

1978

In dissociated single cells from the sponge Geodia cydonium, DNA synthesis is initiated after incubation with a homologous, soluble aggregation factor. During the DNA-initiation phase the cyclic AMP- and cyclic GMP levels vary drastically; the cyclic AMP content drops from 2.2 pmol/10(6) cells to 0.3 pmol/10(6) cells while the cyclic GMP content increases from 0.6 pmol to 3.7 pmol/10(6) cells. The activity of neither the adenylate cyclase nor of the guanylate cyclase isolated from cells which have been incubated for different periods of time with the aggregation factor, is changed. The soluble as well as the particulate enzyme activities were checked in vitro. The cyclic nucleotide receptor…

Kinetic and functional characterization of a membrane-bound NAD(P)H dehydrogenase located in the chloroplasts of Pleurochloris meiringensis (Xanthoph…

1996

Using isolated chloroplasts or purified thylakoids from photoautotrophically grown cells of the chromophytic alga Pleurochloris meiringensis (Xanthophyceae) we were able to demonstrate a membrane bound NAD(P)H dehydrogenase activity. NAD(P)H oxidation was detectable with menadione, coenzyme Q0, decylplastoquinone and decylubiquinone as acceptors in an in vitro assay. K m-values for both pyridine nucleotides were in the μmolar range (K m[NADH]=9.8 μM, K m[NADPH]=3.2 μM calculated according to Lineweaver-Burk). NADH oxidation was optimal at pH 9 while pH dependence of NADPH oxidation showed a main peak at 9.8 and a smaller optimum at pH 7.5-8. NADH oxidation could be completely inhibited with…

2003

Jerboa (Jaculus orientalis) is a deep hibernating rodent native to subdesert highlands. During hibernation, a high level of ketone bodies i.e. acetoacetate (AcAc) and D-3-hydroxybutyrate (BOH) are produced in liver, which are used in brain as energetic fuel. These compounds are bioconverted by mitochondrial D-3-hydroxybutyrate dehydrogenase (BDH) E.C. 1.1.1.30. Here we report, the function and the expression of BDH in terms of catalytic activities, kinetic parameters, levels of protein and mRNA in both tissues i.e brain and liver, in relation to the hibernating process. We found that: 1/ In euthemic jerboa the specific activity in liver is 2.4- and 6.4- fold higher than in brain, respective…

Alterations inras-gene expression and intracellular distribution of protein kinase C in the spongeGeodia cydonium in response to marine pollution

1990

The siliceous spongeGeodia cydonium Jameson was used to study the influence of pollution in marine environments on selected parameters of the intracellular signal transduction pathway. The parameters chosen were: intracellular distribution of protein kinase C (PK-C),ras-gene expression and DNA polymerasealpha (DNA Polalpha) activity. Both PK-C andras-gene product (ras-protein) have previously been established to be key molecules in the intracellular signalling pathway in sponges; increased level ofras-protein mediates events following sponge cell-cell contact. Three unpolluted and three polluted sites in the off-shore seawater around Rovinj (Yugoslavia) were selected for the study in 1989. …