The Effects of Toxic Agents Upon the Action of Bromelin

Botanical Gazette1905Vol. 39(6), pp. 409–419

Abstract

1. Impure preparations of bromelin are strongly autodigestive in acid or alkaline media, such digestion beginning when the breaking up of proteid impurities has been completed and proceeding to total destruction of the enzyme. 2. The effects of poisons vary with the purity of the preparation used, slight amounts of proteid impurities rendering necessary an enormous increase of concentration in order to inhibit action. 3. The toxic strengths of the salts used maintain a constant relationship irrespective of the purity of the enzyme used, i. e., silver is always most poisonous, copper third, zinc sixth, and so on. 4. Bromelin, when prepared in a relatively pure condition is not at all autodigestive, the presence of some proteid of the juice apparently being a prerequisite for such action. 5. Such preparations appear to be in reality a mixture of two enzymes, one active in alkaline solutions, slightly more resistant to poisons, and twice as great in amount as the other, which is active in acid media and is destroyed by heating to 65⚬C. in saline solution. 6. The limits of toxicity and non-toxicity are somewhat more clearly defined than has been the case in experiments upon living organisms (5, 11, 12, 18, 19, 25). 7. The results obtained agree in general with Mathews's arrangement of the metals upon the theory that "the affinity of the atom or ion for its electrical charge is the main factor determining its physiological action." Cadmium in my experiments occupies the position it should hold in accordance with this theory, while barium is far out of place.

Abstract

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