Potassium Phosphate Buffer Solution Research Articles

Effects of Triethanolamine and Related Compounds on the Enzyme Activity of Glutamic Acid Dehydrogenase

An investigation was attempted to determine the effects of triethanolamine, monoethanolamine, ammonium sulfate, hydrazine hydrate and hydroxylamine hydrochloride on the enzyme activity of glutamic acid dehydrogenase which is a pyridine enzyme playing an important role in the oxidation and reduction of living bodies. Results obtained were as follows:1) Sodium glutamate and DPN were dissolved in a potassium phosphate buffer solution. Immediately after addition of the enzyme solution to the buffer, each of the above reagents in different concentrations was added to determine the effects of the mixtures on the enzyme activity for 6 minutes. Triethanolamine, monoethanolamine and hydrazine hydrate enhanced the enzyme activity. The largest increase, about 46%, was observed in the monoethanolamine mixture at the final concentration of 3.3×10 -2 M. The second largest increase was found in triethanolamine and the smallest in hydrazine hydrate.2) Hydroxylamine hydrochloride and ammonium sulfate inhibited the activity of glutamic acid dehydrogenase; ammonium sulfate inhibited the enzyme activity by about 50% at the final concentration of 5.0×10 -3 M, and the percentage was higher than that caused by hydroxylamine hydrochloride.

Study on the rate of epimerization of amoxicillin β-penicilloic acid to its α-form in aqueous solutions using high-performance liquid chromatography

Using automated high-performance liquid chromatography, a preliminary study on the rate of conversion of β-penicilloic acid to its α-form in aqueous solutions, using amoxicillin penicilloic acid as an example is described. An octadecyl-silica column eluted with 0.05 M potassium phosphate buffer solution (pH 5.9) with detection at 228 nm was used for this study. The conversion rate was found to follow pseudo first-order kinetics.

The Spectrophotometric Determination of Perchlorate Ions by Solvent Extraction with Crystal Violet

Abstract A micro quantity of perchlorate ions is extracted into chlorobenzene with crystal violet. The absorbance maximum of the extract in the organic layer is found to be at 595 mμ. The maximum and the constant extraction was obtained in the pH range of 2–7. In order to ascertain the optimum conditions for the determination of perchlorate ions, various factors have been studied: the effects of the concentration of the dyestuff, the pH of the solution, the standing time of the solution, the times of the extraction, and the presence of diverse ions. The recommended procedure for the calibration curve is as follows: Two milliliters of a crystal violet solution (1×10−3 m), 5 ml of a potassium phosphate buffer solution (1 m, pH 5.8), and various volumes (0–10 ml) of a standard perchlorate solution (2×10−5 mol/l) are mixed. The mixed solution is diluted to 25 ml with water. An aliquot (10 ml) of the solution is then poured into a separatory funnel and is shaken for 5 min with 10 ml of chlorobenzene. The absorbance of the organic layer is measured at 595 mμ against the reagent blank solution. Beer’s law is obeyed in the perchlorate range of 10−7–8×106 mol/l in the aqueous layer before the extraction. Considerable amounts of chloride, iodate, and sulfate ions do not interfere.

STUDIES ON THE AMOEBA-TO-FLAGELLATE TRANSFORMATION OF TETRAMITUS ROSTRATUS.

The amoebae of Tetramitus rostratus growing with Escherichia coli were inoculated into a yeast peptone broth and a potassium phosphate buffer solution, and flagellate formation was studied. In both, the numbers of flagellates formed and their proportional incidence increased with the number of amoebae inoculated. In buffer the numbers of flagellates reached a peak at 10 hours, and in broth at 23 hours.Comparisons between the buffer and broth, using the same inoculum, indicated that population density is only one factor governing flagellate formation, since this transformation was greater in buffer for a given population.Replacement of E. coli with four other monoxenic associates indicated that bacterial flora makes little difference in buffer on flagellate transformation, as flagellates were formed with all four genera. A search for a "flagellating substance" produced in the medium or within the cells was not successful.

Metal-Solution Potentials of Nickel in Foreign Ion Solutions

Metal-solution potentials of nickel in foreign ion solutions were investigated. It was found that nickel may show stationary potentials in potassium hydroxide and phosphate buffer solutions, if oxygen was excluded. The stable potentials were reversible with respect to a change of pH. It was noted that nickel was unable to displace hydrogen from a 0.1 M phosphoric acid solution; nickel dissolved only on admission of air. The possibilities of interpreting the observed potentials are discussed.

The properties of mammalian striated myofibrils isolated by an enzymatic method.

A new method for the isolation of large numbers of individual myofibrils from fresh mammalian skeletal and cardiac muscle has been described. Purification of isolated myofibrils was accomplished by differential centrifugation of fresh frozen sections of muscle which had been mechanically agitated after exposure for 30 to 45 minutes at 0 degrees C. to the action of a dilute solution of trypsin in a phosphate buffer solution with a pH of 7.0 and an ionic strength of 0.25. Isolated skeletal myofibrils of the rabbit and man have similar constant solubility properties. They dissolve in an aqueous mixture of 0.5 N potassium chloride and 0.03 N sodium bicarbonate, giving viscous solutions which exhibit conspicuous birefringence of flow. They are soluble in buffer solutions (ionic strength 0.15) on the acid side of pH 4 and alkaline side of pH 10. If the ionic strength of potassium phosphate buffer solutions is increased to 0.5 or if the ionic strength of phosphate-borate buffer solutions is increased to a similar value by addition of potassium chloride, the isolated myofibrils become soluble at neutrality. Hence, it is possible, first to isolate the myofibrils and then dissolve them without deviating appreciably from physiologic ranges of pH. The extent to which myofibrils are modified by the conditions imposed by the method of isolation is unknown. There is no significant change in microscopic structure or optical birefringence. Furthermore, there is retention of a form of physiological reactivity, for when the isolated skeletal myofibrils are immersed in solutions of adenosinetriphosphate, they promptly and irreversibly change from elongated fibrils with distinct structural detail into dense spherical masses without recognizable microscopic structure.