Selective inhibition of mammalian diamine oxidase by aquatic biotoxins

Abstract

The inhibitory activity of saxitoxin and tetrodotoxin on diamine oxidase and S-adenosyl-l-methionine decarboxylase from mammalian sources have been analysed. Unlike tetrodotoxin, saxitoxin was a reversible non-competitive inhibitor of pig kidney diamine oxidase with an estimated K(i) of 140 mum. S-Adenosyl-l-methionine decarboxylase from a highly purified source was not affected by the concentrations tested of either biotoxin. A possible analytical application of this finding is discussed.