Search results for "Trichloroacetic Acid"
showing 4 items of 14 documents
Fluorescence enhancement of quinolines by protonation.
2020
A study of the fluorescence enhancement of isoquinoline, acridine (benzo[b]quinoline) and benzo[h]quinoline is reported with six organic acids of different pKa values. Protonation was found to be an effective tool in the fluorescence enhancement of quinolines. A significant increase in the fluorescence intensity is observed only when strong acids are used, resulting in an over 50-fold increase in fluorescence with trifluoroacetic or benzenesulfonic acid and isoquinoline in a 1.5 : 1 ratio. The benzenesulfonic acid was found to be the most effective in the protonation of the bases despite its higher pKa value compared to trifluoro- and trichloroacetic acid. The X-ray crystal structures of 14…
Xenograft rejection in marine sponges. Isolation and purification of an inhibitory aggregation factor from Geodia cydonium.
1981
In sponges there exists a graft rejection mechanism in which an inhibitory aggregation factor is involved. The inhibitory aggregation factor has been isolated from a culture medium containing dissociated cells of the sponge Geodia cydonium. Using ion-exchange and gel fractionation the factor was purified and shown to be electrophoretically pure. The factor has a molecular weight of 27000 and was characterized as a glycoprotein. The activity of the inhibitory aggregation factor was not affected by heat treatment, but treatment with trichloroacetic acid resulted in the irreversible loss of activity. The inhibitory aggregation factor affects the aggregation-factor-mediated reaggregation of dis…
Two proteases from nuclei of rat testis cells. I. Isolation
1987
Abstract Two proteases, assayed with fluorogenic peptides and tentatively designated Rc and Kc, have been isolated from nuclei of rat testis cells by differential extraction with acetic acid, removal of some proteins at pH 4.5, and polyacrylamide gel electrophoresis followed by electroblotting onto nitrocellulose paper. Protease R hydrolyzes t‐Butyl‐oxycarbonyl‐Val‐Pro‐Arg‐7‐amino‐4‐methyl‐coumarin and other peptides in which arginine is joined to 7‐amino‐4‐methyl‐coumarin by amide linkage. Protease Kc has a preference for peptides terminating in lysine‐7‐amino‐4‐methylcoumarin amide. Neither of these proteases is active against Glu‐Phe‐7‐amino‐4‐methyl‐coumarin amide or Carbobenzoxy‐Arg‐7‐…
[21] Assay of blood glutathione oxidation during physical exercise
1995
Publisher Summary This chapter describes a method to accurately measure glutathione (GSH) and glutathione disulfide (GSSG) in the blood of humans and animals that perform physical exercise. With this method, it is possible to assess the oxidative stress associated with physical exercise by measuring changes in the blood GSH/GSSG ratio. Glutathione measurement is performed by a modification of the glutathione S -transferase method of Brigelius et al. This is based on the conjugation of chlorodinitrobenzene with GSH catalyzed by glutathione S -transferase. The adduct formed, S-(2,4-dinitrophenyl)glutathione, exhibits a maximum of absorbance at 340 nm. The precipitation of proteins is carried …