A reversion of the starch-dextrin reaction

In the reversions of enzymic and catalytic processes heretofore recorded, the synthesis has been brought about by a high concentration of the products of analysis, or by the addition of fresh enzyme to a solution that had reached a state of equilibrium. In the starch dextrin reversion the synthesis was attempted in an entirely different and original way, that is, by a rapid increase of temperature of a solution that is near or at the point of equilibrium in relation to substances studied. In accordance with a known law this change of temperature should move the point of equilibrium endothermically.

In studying this phenomenon it must be borne in mind that in the digestion of liquid boiled starch there may be going on coincidently at least three independently but serially related processes which are dependent upon the activities of three enzymes — one, in the depolymerization of the liquid starch into dextrins (amylase); another, in the hydrolysis of dextrins into maltose (dextrinase); and another, in the hydrolysis of maltose into glucose (glucose). Each of these enzymes has its own optimal point of activity; each carries on its own reaction independently of the others; and in each reaction the substances entering into the reaction have their own point of equilibrium of solution independently of the other reactions. Hence it follows that each reaction, in so far as concerns the reversion phenomenon in relation to the enzyme and the concentration of the solution and the temperature, must be studied separately. Conditions may be present that are favorable to the reversion of one of the reactions but not of the others.