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November 1940


Arch Derm Syphilol. 1940;42(5):896-908. doi:10.1001/archderm.1940.01490170146014

About ten years ago Best and McHenry discovered that certain organs of the dog, particularly the gastrointestinal tract and the kidney, contained a substance capable of inactivating histamine.1 To this material they attributed the characteristics of an enzyme, and they suggested the name histaminase. They found that it could be prepared in the form of a stable powder so that chemical and physical properties were more readily studied. These investigators found that certain optimum conditions were essential for the maximum activity of histaminase, namely, incubation with the substrate for twenty-four hours at 37 C. and a hydrogen ion concentration of 7.2. Under these conditions detectable destruction of histamine occurred only after an incubation period of four hours. Best and McHenry also defined a convenient unit of histaminase as the amount necessary to destroy 1 mg. of histamine under the aforementioned optimum conditions.

Using a commercial preparation,2 Felix3 was