This novel and selective probe for hydrogen sulfide (H2S), 7-azido-4-methylcoumarin (AzMC), is useful for monitoring cystathionine B-synthase (CBS) catalyzed reactions, which play a critical role in human sulfur metabolism. Deactivated CBS is characterized by high plasma levels of homocysteine and H2S, resulting in clinical manifestations of numerous disease states. AzMC, used as a fluorgenic probe and concurrent CBS activity, can be used to select compounds for activation or inhibition of this enzyme, and is suitable for high-throughput screening and the development of potential therapeutics. In addition, AzMC has been used as a photoaffinitry probe for the substrate binding site of human phenol sulfotransferase (SULT1A-1 or P-PST-1).
