Determination of the dissociation constants of pea diamine oxidase.
The activity of diamine oxidase [EC 1.4.3.6] (DAO) isolated from pea cotyledons was measured in Britton-Robinson buffers at pH range 5.0-9.6 by spectrophotometric method with E-1,4-diamino-2-butene as substrate. The enzyme has the highest activity at pH = 7.7 and in pH greater than 8.0 it is irreversible denaturated with time. The dissociation constants of the enzyme and enzyme-substrate complex were calculated by Dixon's method from plots of log Vmax, log KM and log Vmax/KM against pH. The pKEA = 6.5 suggests that histidine is in active site of DAO.
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Department of Analytical and Organic Chemistry, Faculty of Science, Palacký University, Czechoslovakia.
Haviger
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Frébort
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D006631:Amine Oxidase (Copper-Containing) / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D002374:Catalase / Q000378:metabolism; D007887:Fabaceae / Q000201:enzymology*; D006639:Histidine / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D010946:Plants, Medicinal
D006639:Histidine; D002374:Catalase; D006631:Amine Oxidase (Copper-Containing)