Showing papers in "Archives of Biochemistry and Biophysics in 1984"

TL;DR: The authors' entry into the polyamine field was accidental, but their attention was drawn to a report that the rapid senescence of detached leaves of this plant could be delayed substantially by the application of arginine, and this work was started on cereal leaf protoplasts.

TL;DR: The effects of menadione (2-methyl-1,4-naphthoquinone) metabolism on intracellular soluble and protein-bound thiols were investigated in freshly isolated rat hepatocytes and it was suggested that the loss of protein sulfhydryl groups, like that of GSH, was mainly a result of oxidative processes occurring within the cell during the metabolism ofMenadione.

TL;DR: It is proposed that the oxidative stress induced by menadione metabolism in isolated hepatocytes results in the depletion of both soluble and protein thiols, and that the latter effect is critically associated with a perturbation of Ca2+ homeostasis and loss of cell viability.

TL;DR: An H2O2-requiring oxygenase found in the extracellular medium of ligninolytic cultures of the white rot fungus Phanerochaete chrysosporium was purified by DEAE-Sepharose ion-exchange chromatography and gel filtration on Sephadex G-100, indicating an available coordination site and that the heme iron was high spin.

TL;DR: It was determined that crocidolite, chrysotile, and amosite asbestos were all able to catalyze the generation of toxic hydroxyl radicals from a normal byproduct of tissue metabolism, hydrogen peroxide, indicating a major role for iron in the catalytic process, and suggesting a possible mechanism by which asbestos toxicity might be reduced.

TL;DR: It was shown that it is apparently impossible for any calcification to occur in a system which contains a constant, physiological concentration of inorganic pyrophosphate, and this study suggests that the means of assessing the relative importance of a calcification inhibitor should be altered.

TL;DR: This enzyme is capable of initiating the synthesis of the major long-chain bases, as well as compounds that may constitute the unidentified bases reported in analyses of mammalian sphingolipids.

TL;DR: The biantennary pentasaccharide (penta-2,6) was a 500-fold more potent inhibitor than N-acetyllactosamine, suggesting that it might interact with both saccharide-binding sites of the Datura lectin simultaneously.

TL;DR: Results are inconsistent with the occurrence of a reaction of this type during nitrite oxidation and the uptake of extracellular phosphate was sufficient to allow significant transfer of 18O from phosphate to nitrate if oxidative phosphorylation had occurred by way of a P-O-N anhydride between phosphate and nitrate.

TL;DR: Mechanisms of H2O2-induced cell injury were explored in primary cultures of rat hepatocytes, finding that the first pathway is prevented by the antioxidants DPPD and promethazine and is very likely related to the peroxidation of membrane phospholipids.

TL;DR: Findings help explain the unique effects of Leu compared with Val and Ile on branched-chain amino acid metabolism and the differences between control of the kinases associated with pyruvate dehydrogenase and brancher-chain α-ketoacid dehydrogenases.

TL;DR: The mechanisms of H2O2 reduction is shown by analysis of the structural changes observed in the intermediates, and a correlation is shown between the ratio of peaks in the low k (ligand field indicator ratio) region, the Fe-Np average distance, and the magnetic susceptibility, which provides a sensitive indicator of spin state.

TL;DR: In a system reconstituted with NADPH-cytochrome P-450 reductase, NADPH, and phospholipid, purified cytochromes P- 450f and b were discovered to promote conversion of retinoic Acid to polar metabolites, including 4-hydroxy-retinoic acid.

TL;DR: In this article, the effects of detergents and octylamine on female mouse liver flavin-containing monooxygenase activity were characterized for whole homogenates and microsomes prepared under conditions which tend to cause or minimize microsomal aggregation.

TL;DR: Hemorrhagic toxin f (HT-f) was isolated from Crotalus atrox (Western Diamondback Rattlesnake) venom by a five-step purification procedure and was shown to differ immunologically from other hemorrhagic toxins such as HT-a and HT-c.

TL;DR: Investigation of changes in bands assigned to OH deformations in the trehalose suggest that the interaction between the carbohydrate and membrane is by means of hydrogen bonding between these -OH groups and membrane components.

TL;DR: Desferrioxamine-Fe3+ was unique among the chelates tested in that it was a relatively inert iron chelate, having only minor effects on NADPH oxidation and/or O(2) generation by the purified reductase, intact microsomes, or xanthine oxidase.

TL;DR: It would appear that the complex which P-450LM2 forms with its substrate allows considerable movement of the substrate molecule, such that most of the hydrogens in the substrate are exposed to the enzymatic hydrogen abstractor.

TL;DR: Results imply a major difference in reactivity between free and enzymatically generated paraquat radicals, and suggest that the latter could react as an enzyme-paraquat radical complex, for which the relative rate of reaction with Fe3+ (chelate) compared with O2 is greater than is the case with free paraqu at radicals.

TL;DR: The enzyme was protected against redox inactivation by low concentrations of GSSG, ferricyanide, GSH, or dithiothreitol, and high concentrations of NAD(P)+; oxidized glutathione effectively protected the enzyme at concentrations even lower than GSH.

TL;DR: There is a qualitative and quantitative change in the ganglioside antigens in chicken brain and retina during development, and the less sialylated antIGens appear first, followed by the more sIALylated ones, as revealed by orcinol reagent.

TL;DR: The results indicate that the ability of iron to promote hydroxyl radical production and the role that superoxide plays as a reductant of iron depends on the nature of the system as well as the chelating agent employed.

TL;DR: The effect of superoxide dismutase and catalase indicated that O-.2 and H2O2 were essential reactants, while the formation of authentic HO was confirmed by the inhibiting capacities of formate, t-butanol, and mannitol.

TL;DR: A glucan elicitor from cell walls of the fungus Phytophthora megasperma f.

TL;DR: The stoichiometric relationship among photosystem II complexes, photosystem I complexes, cytochrome b/f complexes, high-potential cy tochrome b-559, and chlorophyll in spinach chloroplasts has been determined.

TL;DR: Dissociation in substrate specificity, as well as differences in the inhibition profile, distinguish the enzyme activity in the particulate fraction from rat basophil leukemia cell homogenates from the microsomal glutathione S -transferase which has been described in rat liver homogenate, suggesting that this “leukotriene C synthetase” is a new and unique enzyme.

TL;DR: ESR spectroscopy is a sensitive method of detecting changes in membrane order accompanying peroxidation of membrane lipids, and 12-doxylstearic acid was the most sensitive to the changes in membranes organization caused byperoxidation.

TL;DR: It is demonstrated that HSA plays an essential role in vitro in the synthesis and release of PAF from human PMN, and the hypothesis that there is a cyclic PAF synthesis-release coupling mechanism in the stimulated human PMn is supported.

TL;DR: Kinetic data derived from this study, coupled with data from previous physiological studies from this laboratory, suggests that carnitine transport by the brush border membrane is not limiting for carnitin reabsorption, and down-regulation of carnitines transport may prevent excessive or toxic accumulation of L-carnitine in renal tubular cells exposed to high extracellular carnite concentrations.

TL;DR: The level of tyrosinase activity in Cloudman melanoma cells is a direct reflection of the abundance of enzyme protein, directly proportional to the increase in enzyme activity.