Use Of Anions Research Articles

Formation of δ-aminolevulinic acid from glutamic acid by a partially purified enzyme system from wheat leaves

A method for partial purification of an enzyme system from greening wheat leaves which converts 14C-labeled glutamate to δ-aminolevulinic acid is described. The purification entails the successive use of anion and cation exchange, followed by moleculr sieving. The enzyme system is unstable in crude form, but the stability is markedly increased after column chromatography on CM-cellulose. The pH profile and the cofactor requirements suggest that at least two enzymes are involved.

The polarographic reduction of perbromate and its use as a probe of double layer structure

o 1. The reduction of perbromate has been studied in dilute (1, 10 and 100 m M ) aqueous alkali halide solutions, in which they exhibit a polarographic minimum and an associated negative faradaic admittance. 2. In electrolytes which exhibit only weak specific ion adsorption ( e.g. , 0.1 M NaF), the perbromate reduction is characterized by a low and apparently potential-dependent transfer coefficient. 3. The marked effects of the adsorbable ions Cl − , Br − and I − can be accounted for quantitatively by the Frumkin correction, using classical double layer theory and assuming that the intrinsic perbromate reduction rate is not affected by specific halide adsorption. 4. The 1 m M electrolyte solutions, the charge density due to specifically adsorbed Cl − and F − almost equals the electronic charge density, but the double layer potentials do not vanish. 5. Specific advantages of the use of anions as quantitative probes of double layer structure have been outlined.

The amount of some organic acids found in TMV-infected tobacco leaves floated on water or on various organic acids

The upper surface of some tobacco leaves and the lower surface of other leaves were inoculated with TMV. After being inoculated, these leaves were floated on water, succinate, malate, or acetate with their lower surface resting on the liquid and were illuminated continuously by means of fluorescent lamps at 25° C. After a definite period, through the use of anion and cation exchange resins, the amounts of individual organic acids in extracts of these leaves were estimated. The amounts of succinic, malic, citric, and fumaric acids in the leaf tissues which had been inoculated on their lower surface and then floated on water for 1 day after inoculation, did not differ from that in the noninoculated tissues. However, when the leaves were floated on succinate, the inoculated leaves contained more malic acid than the noninoculated leaves. A similar increase was observed with some leaves floated on malate, but not with others. In contrast, inoculation on the upper surface of the leaves, whose lower surface then was floated on malate or acetate, did not cause any alteration in the amount of malic acid found in the leaves 1 day after inoculation.

Factors affecting extraction and recovery of follicle stimulating hormone from sheep pituitary glands.

Summary(1) The effect of salt concentration and pH during extraction of sheep pituitary tissue, and temperature and pH of fractionation of these extracts on the preparation of FSH were studied. The most highly purified FSH from the biological standpoint was obtained by extracting at pH 5 with saturated NaCl solution and fractionating at pH 2.5 and 30°C. (2) The FSH preparations made by extracting with 90% saturated and saturated NaCl at pH 5, 5.5 and 6 and fractionating at 30°C and pH 2.5 contained little LH. (3) These preparations were free of ACTH and TSH at the levels tested. (4) The FSH can be concentrated and purified by use of anion and cation exchange resins. (5) Preparations made from 80% saturated NaCl extracts and from extracts made at pH 8 and 9 with saturated NaCl contained significant amounts of LH.