Catalase was not noticed until 1818 when Louis Jacques Thénard, who discovered H2O2 (hydrogen peroxide), suggested its breakdown is caused by an unknown substance. In 1900, Oscar Loew was the first to give it the name catalase, and found it in many plants and animals.[9] In 1937 catalase from beef liver was crystallised by James B. Sumner and Alexander Dounce[10] and the molecular weight was found in 1938.[11]
In 1969, the amino acid sequence of bovine catalase was discovered.[12] Then in 1981, the three-dimensional structure of the protein was revealed.