| Description |
Hydrogen sulfide (H2S) is a toxic gas with a distinct rotten-egg odor. While the detrimental affects of H2S on human health have been known for hundreds of years, it has recently become apparent that low levels of endogenously produced hydrogen sulfide are cytoprotective. In fact hydrogen sulfide is an important signaling molecule in a variety of systems resulting in a large range of physiological effects, from vasodilatory to antiinflammatory. However, the exact roles played by hydrogen sulfide, its concentrations in serum and tissues, and the enzymes that produce it are still being investigated. It seems that a lack of tools with which to accurately measure in vivo concentrations of hydrogen sulfide has stalled progress in the field. Herein we report several novel, fluorescent probes with which to detect endogenous concentrations of hydrogen sulfide both in vitro and in biological samples. These probes utilize an arylazide moiety that is selectively reduced by hydrogen sulfide to produce a signal. We show that this signal is concentration-dependent in a linear manner up to 300 !M hydrogen sulfide. We also show that these probes are sensitive down to 200 nM hydrogen sulfide. Additionally, we have applied these probes in assays to study hydrogen sulfide-producing enzymes, cystathionine "-synthase (CBS), cystathionine #-lysase (CGL), and tryptophan synthase (TS). By discovering selective inhibitors of these enzymes, we can modulate hydrogen sulfide production in vivo. Lastly, we have applied a series of lanthanide-based fluorescent probes to detect hydrogen sulfide in the petrochemical industry. These probes utilize a similar arylazide moiety as an antenna. The lanthanide center can be excited after reaction with H2S to give a signal with a long lifetime. By delaying the readout, it is possible to see this signal over a highly fluorescent background, such as crude oil. These probes have been used to study the presence of hydrogen sulfide in two sour water samples as well as five samples of crude oil obtained from the Tesoro Corporation. |
