Abstract
Kinetic studies were made on the reaction of nitrous acid and lecithinase, purified from Formosan cobra venom. The decreased activity of lecithinase in the presence of excess nitrous acid in acetate buffer is a first-order reaction and its reaction rate is extremely slow as compared to deamination reaction, the half-life being 270 minutes at pH 4.0 and 390 minutes at pH 4.4. The lecithinase partially inactivated by nitrous acid does not recover its activity by application of hydrogen sulfide. These facts suggest that the principle of lecithinase activity is independent of amino or mercapto group and is situated in the phenol, that is, in tyrosine.
