The Nature of the Respiratory Supplement.

Abstract

When the oxygen consumption of rabbit erythrocytes and that of saline extracts of rat livers (or various other organs), are measured separately, and compared with what happens in a mixture of both, the oxygen consumption is much higher in the mixture than the sum of the oxygen consumptions in the 2 separate systems. This has been shown by the authors previously 1 ; the effect of the liver extract has been confirmed by Zeile and Euler. 2

This'paper presents the attempts to elucidate the nature of this reaction. For brevity's sake the active principle of the liver extract will be designated as the respiratory supplement.

1. The supplement deteriorates and may even be destroyed by various mechanical treatments of the liver extract. Extended shaking, in presence or in absence of oxygen damages the supplement. When the extract is centrifuged the supplement activity both of the sediment and of the supernatant fluid is diminished and by mixing the 2 fractions is not restored to its original strength.

2. Several attempts were made to isolate the supplement by adsorption. Sand, Kaolin, Kieselgur adsorb the supplement to only a small extent, according to the amount applied, but never completely. Colloidal iron hydroxyd adsorbed the supplement completely in several experiments, in which the adsorbent was used in an amount sufficient to remove the proteins. Colloidal aluminum hydroxyd removed it completely when applied in so small an amount as to remove only a small part of the proteins. No attempt to recover the supplement by elution with N/20 ammonia was successful.

3. Heating to 56° diminishes the supplement considerably though there is no critical temperature for this effect. The inactivation by heat seems to run parallel to the formation of a coarse turbidity or flocculation in the previously slight and homogeneous extract.