The Action of Cyanides and Nitriles on the Spontaneous Oxidation of Cystein. by A. P. Mathews

It is well known that the cyanides and the nitriles when given to mammals leave the body in part as sulfocyanides. This suggests that they combine with the labile sulfur group of the albumins of the cell, and it was this fact which led us to undertake a study of the spontaneous oxidation of cystein. It is not necessary to recapitulate the evidence that the cyanides act on cell-respiration, since all observations are practically unanimous that they do.’ Carlson’s observation that the heart ganglion of Limulus may be recovered from cyanide poisoning by washing out the ganglion with hydrogen, while in itself very interesting in no way invalidates this conclusion, since the probable identity of aerobic and anaerobic respiration would lead one to anticipate his results. The action of potassium cyanide on the spontaneous oxidation of cystein is striking. Very small amounts of the cyanide check this oxidation while larger quantities inhibit it completely for a time, although ultimately, possibly owing to the oxidation of the cyanide, the cystein escapes from the retarding action and proceeds slowly to oxidize. This is true for the spontaneous oxidation both when catalyzed by iron and when not catalyzed. Nitriles also check this oxidation. The experiments were performed in the same manner as described in the preceding papers.3 The readings of the manometer was made at ten or fifteen minute intervals. Two grams of cystein were in each flask in 50 cc. of solution and the reaction was always carefully noted and in general was a blue violet to