On some properties of catalase haematin

It was shown recently by Zeile and Hellström (1930) that a strong preparation of catalase obtained from horse liver has the distinct absorption spectrum of a haematin compound. The concentration of this haematin compound in various fractions of their preparations, estimated as pyridine haemochromogen, was found to be proportional to the enzyme activity of these fractions. They have also shown that the factors which abolish or inhibit the activity of the enzyme, such as high temperature, alkali, acids, or the addition of small amounts of KCN or H₂S, modify also the absorption spectrum of the haematin.