The inhibition of pea diamine oxidase (DAO; EC 1.4.3.6) by some amines and chelating agents has been studied. Ethylenediamine (competitive, Ki = 5.2 mmol.l-1), cis-1,2-diaminocyclohexane (noncompetitive, Ki = 2.9 mmol.l-1) and trans-1,2-diaminocyclohexane (competitive, Ki = 3.6 mmol.l-1) are weak inhibitors whereas diethylenetriamine (noncompetitive, Ki = 7.2 mumol.l-1), triethylenetetraamine (partial noncompetitive, Ki = 0.57 mumol.l-1) are potent inhibitors. The chelating agents 1,10-phenanthroline (Ki = 0.031 mmol.l-1), and 2,2'-bipyridyl (Ki = 0.058 mmol.l-1) are noncompetitive inhibitors. The pH-inhibition profile for the inhibitors indicates that the protonated forms are the active species.

Department of Analytical and Organic Chemistry Faculty of Science Palacký University Olomouc Czechoslovakia

References provided by Crossref.org

Inhibition of diamine oxidases and polyamine oxidases by diamine-based compounds