The Effect of Acetylation on the Properties of Beef Liver Catalase

• Published in: Journal of biochemistry (Tokyo) 1964-11, Vol.56 (5), p.416-423
• Main Authors: HIRAGA, MASAZUNI, ANAN, F.K., ABE, K.
• Format: Article
• Language: English
• Subjects: Acetates; Acetylation; Animals; Catalase; Cattle; Chromatography; Electrophoresis; Liver - enzymology; Old Medline; Peroxidases
• ISSN: 0021-924X; 1756-2651
• DOI: 10.1093/oxfordjournals.jbchem.a128012

Crystalline beef liver catalase was acetylated by adding acetic anhydride at pH 8 and 0–4°C. The acetylated products were dialyzed and dissolved in a weakly alkaline solution at pH 8. Acetylation of catalase increased the reactivity of the tyrosine (plus tryptophan) residues along with the increasing degree of acetylation. The reactivities of histidine (plus tyrosine) and arginine groups were slightly increased to an extent comparable with those of the control (unacetylated) catalase, which had been denatured to some extent during dialysis against distilled water. Electrophoretic mobility of acetylated catalase at pH 8.6 was higher in the ascending order of acetylation degree. With increasing degree of acetylation, the catalase activity was progressively diminished and, in turn, the peroxidase activity was gradually enhanced. Acetylation shifted the Soret band of catalase to 415 mμ. Highly acetylated catalase was readily reducible with dithionite, and, in the presence of CO, it was converted to the carbomonoxy derivative. The results have led us to a conclusion, for the present, that an outer unstable part of the catalase molecule is mainly modified by acetylation, whereas an inner rigid part is not likely unfolded.