The hœmatin content of horseradish peroxidase

In 1931 Kuhn, Hand, and Florkin claimed to have shown a parallelism between the enzymic activities and the very small hæmatin contents of purified horseradish peroxidase preparations and they suggested that the enzyme is probably a hæmatin compound. It was shown previously (Keilin, 1927) that the hæmatin content of horseradish is sufficiently high to be directly seen in slices of horseradish when transformed into hæmochromogen and that similar hæmatin compounds are very widely, if not universally, distributed in the cells of various organisms. The objects of this study was, firstly, to determine the relationship between the hæmatin compound, which can so easily be detected in plant tissues and the hæmatin found in various purified peroxidase preparations, and to investigate the nature and the state of this hæmatin compound.