[Bicentennial of catalase research, 1818-2018].

L. J. Thénard and J. L. Gay-Lussac discovered hydrogen peroxide in 1818. Later, Thénard noticed that animal and plant tissues decompose hydrogen peroxide. The substance which is responsible for this reaction was named as catalase by O. Loew in 1900. The catalase enzyme was regarded as a diagnostic and a tumour marker in the late years of the 19th century and in the early years of the 20th century. Acatalasemia, an inherited deficiency of enzyme catalase, was studied in Japan, Switzerland and Hungary. The recent findings on catalase are focusing on the effects of reactive oxygen species and on the association of acatalasemia and diabetes mellitus. Orv Hetil. 2018; 159(24): 959-964.