ENZYMATIC CONVERSION OF CYANIDE TO THIOCYANATE

Abstract

The ability of various tissues of the dog, rhesus monkey, rabbit and rat to convert -CN to -CNS in vitro was studied. A system containing phosphate buffer pH 7.4, 0.42 [image] Na2S2O3, 0.3 ml. homogenate, 0.14[image] KCN in a total vol. of 9.2 ml. added in the order named and shaken for 15 min. at 37.5 C gave conditions near the optimum for all tissues. Enzymatic activity was detd. by measuring photometrically the color produced by reaction of Fe(NO3)3 with the -CNS formed. Thiosulfate was the only S. compound found capable of efficiently supplying S to the in vitro system. In the dog, the suprarenals contained the highest enzyme concn. followed by the liver, various parts of the brain and spinal cord, kidney, and testes. Tissues such as heart, intestine, spleen, lung, muscle, and salivary gland had smaller quantities, while the enzyme content of erythrocytes and plasma was barely measurable. In the monkey, rabbit, and rat, the liver contained the highest concn. of enzyme, it being much higher than in the dog. The enzyme contents of the kidney, heart, and muscle of the monkey, rabbit, and rat were also much higher than the dog tissues. The other organs and the parts of the central nervous system, however, ranked with the same tissues from the dog. The species grouped according to increasing activity of their liver and kidney homogenates were dog, monkey, rabbit, and rat.