Carbon monoxide: medicinal chemistry and biological effects.

Carbon monoxide (CO), which is classically thought of as a toxic molecule and cellular asphyxiate, has become increasingly recognized as an important molecule in the physiological regulation of multiple organ systems and in the restoration of homeostasis in pathophysiological states. CO has long been utilized as a tool in chemistry and physiology secondary to its ability to bind to heme proteins. Additionally, CO is produced endogenously in the breakdown of heme by heme oxygenase enzymes. Here we review the biological chemistry of CO and highlight some of the anti-inflammatory biological effects of the heme oxygenase/CO system.