Inorganic Ortho Research Articles

Synthesis and evaluation of carbaborane derivatives of indomethacin as cyclooxygenase inhibitors

Nonsteroidal anti-inflammatory drugs (NSAIDs) exert their pharmacological activities by inhibiting cyclooxygenase (COX)-1 and COX-2. Previous studies have shown that esters and amides of non-selective inhibitors such as indomethacin are selective against COX-2, which is the therapeutically relevant isoform. Structure–activity analysis indicates that substituted phenyl rings are tolerated as ester components. In the present study, the introduction of inorganic ortho- and meta-carbaborane moieties was explored with the aim to create COX-2 inhibitors and more importantly to investigate the validity of using these boron clusters as drug entities. Interestingly, only the ortho-carbaborane ester was active whereas the meta isomer was not. A similar lack of inhibitory potency was observed when an adamantyl substituent or alkylene spacers at the carbaborane were introduced in the ester functionality.

Calcium-binding capacity of organic and inorganic ortho- and polyphosphates

The aim of this research was to determine the calcium-binding capacity of inorganic and organic ortho- and polyphosphates. This calcium-binding capacity can be used to influence the stability of, for example, casein micelles in dairy systems. Four phosphates were selected: disodium uridine monophosphate (Na2UMP, organic orthophosphate), disodium hydrogen phosphate (Na2HPO4, inorganic orthophosphate), sodium phytate (SP, organic polyphosphate), and sodium hexametaphosphate (SHMP, inorganic polyphosphate). Concentrations of up to 100 mmol·L−1 phosphate were added to a 50 mmol·L−1 CaCl2 solution. The samples were prepared at pH 8.0 and were analyzed before and after sterilization for calcium-ion activity, conductivity, pH, sediment, and turbidity. Both SHMP and SP are strong chelators, as calcium ions bind to these phosphates in the ratio of 3:1 and 6:1, respectively. Calcium ions also strongly bind to Na2HPO4, but in aratio of 3:2 with insoluble Ca3(PO4)2 complexes as result. The equilibrium position of Na2UMP is not strong towards the chelated complex, and significant levels of free calcium and free phosphate can exist. An equilibrium constant of 0.29 ± 0.08 L·mol−1 was determined for calcium uridine monophosphate (CaUMP) complexes. Both calculation of the equilibrium constant and analysis on the CaUMP precipitate confirmed a reactivity of 1:1 between calcium and Na2UMP. The CaUMP complexes are well soluble at ambient temperature, and insoluble complexes appear after sterilization, because the solubility of CaUMP decreases during heating. Finally, we concluded that the structure of phosphate molecules determines their calcium-binding capacity rather than organic or inorganic origin of phosphates.

COMBINED CHEMICAL AND 31P-NMR SPECTROSCOPIC ANALYSIS OF PHOSPHORUS IN WETLAND ORGANIC SOILS1

The organic P (Po) status of wetland soils has a large influence on the internal P cycling, and therefore on the biological productivity and water quality, of wetland ecosystems. Chemical extraction and solution-state 31 P-nuclear magnetic resonance (NMR) spectroscopy were used to identify and quantify the distribution of the major forms of P in organic soils of three created wetland sites-Apopka Marsh, Eustis Muck Farm, and Sunny Hill Farm (SHF). Spectra were obtained on 0.25 M NaOH-0.05 M EDTA extracts of soils with and without previous chemical removal of labile soil P. 31 P-NMR spectral analysis of the NaOH-EDTA extracts revealed the presence of inorganic ortho P (Pi), ortho-P monoesters, and ortho-P diesters. Chemically determined proportions of total P (TP) as Pi in the NaOH-EDTA extracts were similar to those obtained by 31 P-NMR. P monoester was the predominant P form in Apopka Marsh (51% TP) and SHF (59% TP) soils. The Eustis soil contained a high proportion of Pi (65% TP), and the SHF soil contained significant (10% TP) P diester. Chemical removal of labile Pi, using 1 M KCl and 0.5 M NaHCO 3 , enhanced the quality of all NMR signatures and demonstrated that not all P diesters are removed in the NaHCO 3 extract. NMR spectra were obtained with acquisition times ranging from 0.5 to 1.2 h, which represents a significant reduction in data acquisition times reported in the previous 31 P NMR studies of soil extracts.

Transhydrogenase activity in the marine bacterium Beneckea natriegens

The marine bacterium, Beneckea natriegens, which has previously been reported not to form transhydrogenase, has been shown to synthesize a soluble energy-independent transhydrogenase (NADPH:NADP + oxidoreductase, EC 1.6.1.1), though no energy-linked activity could be detected. The transhydrogenase is induced maximally in stationary phase cells and its formation is 70–90% repressed by raising the medium phosphate level from 0.33 to 3.3 mM. The enzyme is inhibited by arsenate, inorganic ortho- and pyrophosphate and by a range of organic phosphate-containing compounds, including 2′-AMP, which is an activator of several bacterial transhydrogenases.

Topography of the electron density in pyrophosphate bonds

Contour maps of the electron density in the phosphorus-oxygen bonds of inorganic ortho- and pyro-phosphate molecules and in the biologically important nucleotide adenosine-5′-diphosphate (ADP) are presented. The densities and overlap populations calculated from approximate molecular orbital methods are used to explain the nature of the so-called “energy-rich” phosphate bond. The P 3d orbitals are able to contribute more to the π bond strength of the terminal P-O bonds than to the P-OP bonds. Equations are introduced for calculating changes in valence electron distributions brought about by molecular formation and for comparing Mulliken populations with spatial distributions of electrons.

Electronic structures for energy-rich phosphates

The extended Huckel theory is applied to adenosine-5′-di- and triphosphate, and to the related molecules of adenosine-5′-monophosphate, inorganic ortho-, pyro- and triphosphate, adenine, D-ribose and adenosine. Charge distributions calculated for these three-dimensional molecules suggest that opposing resonance and electrostatic repulsions can contribute to the high free energies of hydrolysis of the polyphosphates near pH 7. Eigen-values from SCF calculations on small, related compounds are found to be useful as valence state ionization potentials. A procedure for obtaining total energies within the EH framework is described which approximates experimental values better than the sum of the orbital energies. The phosphorus 3d orbitals contribute significantly to the stability of the phosphates. The charges along the backbone of the condensed phosphates alternate in sign. Little interaction is found between the phosphate and base moieties of the nucleotides in folded conformations.

UTILIZATION OF INORGANIC ORTHO-, META- AND PYROPHOSPHATES BY LAMBS AND BY CELLULOLYTIC RUMEN MICROORGANISMS IN VITRO.

UTILIZATION OF INORGANIC ORTHO-, META- AND PYROPHOSPHATES BY LAMBS AND BY CELLULOLYTIC RUMEN MICROORGANISMS IN VITRO.

魚肉の褐変に関する研究-IV

Ultraviolet absorption spectra, fluorescence, and some characteristics on paperchromatography were observed on sugar solution in 0.1M phosphate buffer, pH 6.8 (0.05M) after autoclaving for one hour at 115° in the presence of amino acid 0.05M) Among four amino acids (arginine, lysine, histidine and glycine), lysine shows the strongest accelerating effect for production of brown color and ultraviolet absorption (Table 1). Ultraviolet absorption maximum is found in the region between 268 to 295mμ (Figs. 2 and 3), and the spectra were considered similar to that of reductone rather than furfural. By paperchromatography using n-butanol-acetic acid-water, (4:1:2), the following points were investigated: 1) By ninhydrin, no spot is detected other than amino acid. 2) Amino acid and sugar produce fluorescence without loss of their characteristics as Rf and reactivity for spot detection. 3) Most of brown color is not developed, while fluorescence is moved as same as sugar and amino acid. 4) Inorganic ortho phosphate does not combine with sugar, amino acid, or other reaction products.

高等植物における呼吸と燐酸エステル合成との共軛反応について(第2報)

Decrease of inorganic ortho phosphate in aerobic condition by the whole homogenate of Phaseolus Mungo was reported previously(1). The products of the oxidative phosphorylation in the same system were investigated using P32 as a tracer. Fractionation of the reaction products were carried out as in Fig. 1, and the amounts of inorganic phosphate, tolal phosphate 7 min. phosphate and the relative radio activities of each fraction were listed in Table 1, and P32/P ratioes were shown in Table 2. Figs. 2_??_5 are paper chromatograms and their auto radiograms of these fractions. These results indicatethat phosphate radicals esterifed by this system are transferred mainly in the Ba-soluble and the Ba-insoluble phosphate compoumds. From these results the authors conclude that the oxidative phosphorylation is really accomplished by this system.