THE PROTEINASE INACTIVATION OF CATALASE AND SOME PROPERTIES OF THE DIGESTS

抄録

1. The digestion of catalase protein by pepsin (pH 4.0) or by trypsin (pH 7.4) lowered the catalatic activity gradually. During the digestion, peroxidatic activity for guaiacol was enhanced and increased with the digestion time.
2. During the proteinase digestion the absorption curve of the Soret band shifted to shorter wave-length by 15 mμ. The peptic digest (pH 1.5) and tryptic digest (pH 7.4) of catalase for 24 hours showed such an absorption maximum (390 mμ) of the Soret band.
3. When the digests were developed by paper electrophoresis (veronal buffer, pH 8.6, μ=0.1), the peptic digest (pH 1.5) gave a main band at the starting line. Such an immobile component was alone a product of the acid-treated catalase (pH 1.5). The tryptic digest (pH 7.4) and peptic digest (pH 4.0) yielded only a small amount of the immobile band, but there remained a considerable amount of other components, including the one of the same mobility as that of catalase.
4. The solubility curves of the peptic digest (pH 1.5) and tryptic digest (pH 7.4) in ammonium sulfate, varying in concentration, indicated at least three fractions, respectively. The peptic digest was fractionated at 40 and 85 per cent saturation, and the tryptic at 40 and 70 per cent saturation. Among six fractions, P₂ (the second fraction of the peptic digest) exhibited remarkably strong activities as peroxidase (guaiacol oxidation) and in-dophenol oxidase (Nadi reaction).
The author wishes to express his thanks for helpful advises of Prof. S. Miyamoto and Prof. K. Kaziro, and for technical assistance of Miss H. Suzuki.