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At least 1,513 records · Page 84Linked to original sources
PubMed2003

[Analyses of biogenic related compounds based on intramolecular excimer-forming fluorescence derivatization].

A highly selective and sensitive method based on a novel concept is introduced for the assay of biological substances. This method is based on an intramolecular excimer-forming fluorescence derivatization with a pyrene reagent, followed by reverse-phase HPLC. Polyamines, polyphenols, and dicarboxylic acids, which have two or more reactive functional groups in a molecule, were converted to the corresponding polypyrene-labeled derivatives by reaction with the appropriate pyrene reagent. The derivatives exhibited intramolecular excimer fluorescence (440-520 nm), which can clearly be discriminated from the monomer (normal) fluorescence (360-420 nm) emitted by pyrene reagents and monopyrene-labeled derivatives of monofunctional compounds. With excimer fluorescence detection, highly selective and sensitive determination of polyamines, polyphenols, and dicarboxylic acids can be achieved. Furthermore, the methods were successfully applied to the determination of various biological and environmental substances in real samples, which require only a small amount of sample and simple pretreatment.

Biogenic Polyamines↗
PubMed2000

Biogenic amines in Drosophila virilis under stress conditions.

The effect of heat stress (38 degrees C) on the content of DL-beta-(3,4-dihydroxyphenyl)alanine (DOPA), dopamine, tyramine, octopamine, and their precursor Tyr was studied in adults of two lines of Drosophila virilis contrasting in their stress response. In individuals of line 101 responding to stress by a hormonal stress reaction, the contents of DOPA, dopamine, octopamine, and Tyr were lower than those of line 147 that did not respond to the stress. However, heat stress caused an increase in the contents of DOPA, dopamine, octopamine, and Tyr in line 101, whereas the equivalent titers in line 147 remain unchanged.

Adaptation, Physiological↗
PubMed1975

Oxidative deamination of biogenic amines by intestinal amine oxidases: histamine is specifically inactivated by diamine oxidase.

The ability of the gut to inactivate various amines by oxidative deamination was tested with a 130-fold purified amine oxidase preparation from dog small intestine. Of 34 amines tested, putrescine, benzylamine, cadaverine, and serotonin were the most favourable substrates. Histamine was inactivated rapidly by this enzyme preparation, too. Histamine derivatives methylated at the imidazole nucleus were also deaminated, whereas Nalpha-methylhistamine was only a poor substrate and Nalpha, Nalpha-dimethylhistamine was not a substrate at all. Using a second procedure for the purification of amine oxidases from gut, the separation of a soluble monoamine oxidase from diamine oxidase was achieved by gel filtration on Sephadex G-200. The diamine oxidase deaminated putrescine (Km = 1.3 x 10(-4)M) and histamine (Km = 6.6 x 10(-5)M), but not serotonin, and was inhibited by aminoguanidine, but not by pargyline. The soluble monoamine oxidase inactivated serotonin (Km = 4.5 x 10(-4)M), but not histamine and putrescine and was inhibited by pargyline, but not by aminoguanidine. It was concluded that in dog small intestine (as well as in rabbit small intestine) only diamine oxidase was capable of inactivating histamine by oxidative deamination.

Amine Oxidase (Copper-Containing)↗