抄録
Enzymic properties of diamine oxidase (DAO) and histaminase were compared. The enzymic activities of a partially purified preparation from hog kidney were determined by measuring oxygen consumption using cadaverine and histamine as substrates for DAO and histaminase, respectively. Differences were found in the effects of various reagents on the two activities. Although NH2OH inhibited to a similar extent the activities of DAO and histaminase, NaNO2, (NH4)2SO4 and C2H5OH affected the two activities differently. Moreover, NH2OH and NaNO2 had no effects on the pS curves of the two enzymes. (NH4)2SO4 and C2H5OH had no effect on the pS maximum of histaminase, but shifted the pS maximum to a higher concentration of cadaverine. Furthermore, marked differences in the mechanisms of action of DAO and histaminase were apparent from the effects of NH2OH, NaNO2, (NH4)2SO4 and C2H5OH on the two activities as measured from Lineweaver-Burk plots. These results indicate that the enzymic properties of DAO and histaminase are different and suggest that they are probably different enzymes.
