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Enzymology of H2S signaling (227.2)
Author(s) -
Banerjee Ruma
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.227.2
Subject(s) - cystathionine beta synthase , sulfurtransferase , cystathionine gamma lyase , transsulfuration , biochemistry , chemistry , enzyme , flux (metallurgy) , catabolism , mitochondrion , microbiology and biotechnology , biogenesis , glutathione , atp synthase , rhodanese , biology , cysteine , gene , organic chemistry
Despite the excitement over the discovery of a third gaseous signaling molecule and the consequent profusion of literature on H2S biology, progress in the field has been impeded by the lack of sulfide‐specific sensors for detection/imaging, and an understanding of how cells maintain very low steady‐state levels of H2S, amplifying the signal as needed. We are studying the enzymology of mitochondrial sulfide oxidation, which links it to the electron transport chain and to ATP production. The enzymes of the transsulfuration pathway, cystathionine β‐synthase (CBS) and cystathionine γ‐lyase (CSE) are important for the endogenous production of H2S in addition to the mitochondrial enzyme, mercaptopyruvate sulfurtransferase (MST). We have recently obtained structures of CBS and MST captured with reactive intermediates in the active sites. We have also quantified MST, CBS and CSE levels in murine liver, brain and kidney and assessed the relative contributions of these enzymes to H2S production. We will discuss new data on estimation of hepatic sulfur flux both through H2S biogenesis and O2‐dependent H2S catabolism, which are very high and comparable to the flux of sulfur into the antioxidant pool, glutathione. These data implicate regulation of H2S clearance as a potentially important “off‐switch” in H2S signaling.