The differential reaction of histamine and N tau-methylhistamine with Pauly's diazo reagent: application to assay of histamine N-methyltransferase activity.
A simple nonradioisotopic fluorescent method for assay of histamine N-methyltransferase (HMT) activity was developed. After termination of the HMT reaction, the remaining excess substrate, histamine, was degraded by Pauly 's diazo reagent, whereas the product, N tau-methylhistamine (N- MeHA ), was not degraded by the reagent. Then the mixture was applied to high-performance liquid chromatography under conditions in which N- MeHA was not separated from histamine, and N- MeHA was measured fluorometrically by condensation with o-phthalaldehyde. The method would be convenient for measurement of HMT activity during enzyme purification.
D000818:Animals; D001557:Benzenesulfonates; D001921:Brain / Q000201:enzymology; D002851:Chromatography, High Pressure Liquid; D003979:Diazonium Compounds; D005260:Female; D006632:Histamine / Q000032:analysis*; D006637:Histamine N-Methyltransferase / Q000378:metabolism*; D007202:Indicators and Reagents; D007668:Kidney / Q000201:enzymology; D008761:Methylhistamines / Q000032:analysis*; D008780:Methyltransferases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013050:Spectrometry, Fluorescence; D013425:Sulfanilic Acids; D009764:o-Phthalaldehyde
D001557:Benzenesulfonates; D003979:Diazonium Compounds; D007202:Indicators and Reagents; D008761:Methylhistamines; D013425:Sulfanilic Acids; D009764:o-Phthalaldehyde; C031205:3-methylhistamine; D006632:Histamine; D008780:Methyltransferases; D006637:Histamine N-Methyltransferase; C000469:diazobenzenesulfonic acid