HEPATIC CARBONYL SULFIDE METABOLISM

Carbonyl sulfide (COS) is rapidly metabolized by isolated rat hepatocytes, as determined by COS disappearance. However, upon termination of the reaction by acidification much of the metabolized COS reappears in the headspace of the reaction vessel. The COS disappearance when determined after acidification is equal to the formation of carbon dioxide and an inorganic sulfur containing compound(s). The metabolism of COS by hepatocytes is inhibited by acetazolamine but not by carbon disulfide or inhibitors of the cytochrome P-450 containing monooxygenase system. Upon subcellular fractionation, the majority of hepatic COS metabolizing activity is found in the cytosol. Additional experiments with a partially purified enzyme indicate that COS is a substrate for hepatic carbonic anhydrase. © 1979.