It is generally accepted that modified Euler-Josephson's method of titration gives the value of catalase activity, “Kcat” as the standard value. Whereas by the author's method taking the value of catalase activity as "k" measured, for example, at room temperature, recorded on an autorecording apparatus, it will be seen that we get the formula, Kcat=1/1.035 (100/90K+0.513) The present study has led to the following conclusions: This method is characterized by the fact that it is useful for the screening test for hypocatalasemia as well as for simultaneous measurement of the catalase activity in human blood. It is suggested that the level of the screening be fixed more appropriately at 2.4.
Attempts have been made to use a portable UV-colorimeter to the screening but it seemed that this apparatus is not suitable for the purpose.
This method can measure not only the activity of purified catalase but also that of a partially purified catalase. It can also be applied for the measurement of catalase activity in tissues other than blood. It is anticipated that this method can also be useful for the investigation of hypocatalasemic blood catalase from the aspect of enzyme kinetics.