The cyanide-metabolizing enzyme rhodanese in different parts of the respiratory systems of sheep and dog.

Studies on the rhodanese activity of respiratory systems of sheep and dog showed that a significant difference exists in the pattern of distribution of this enzyme in different parts of the respiratory system of both species. In sheep, larynx, trachea, bronchiole, and lung contain higher activity than nasal cavity and pharynx. In dog, significantly greater rhodanese activity was found in nasal cavity than in other parts of the respiratory system. In regions with high rhodanese activity the enzyme was more concentrated in the mucosa than in the underneath tissues. These results are discussed in terms of the possible role of rhodanese in cyanide metabolism in respiratory tract and the efficacy of this organ in inhaled cyanide detoxification in these species of animals.