Premium
sGC in SMC acts as Nitrite Reductase leading to NO formation
Author(s) -
Madrasi Kumpal Jagdish,
Tsoukias Nikolaos,
Joshi Mahesh
Publication year - 2012
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.26.1_supplement.1131.8
Subject(s) - nitrite , chemistry , nitrite reductase , nitric oxide , dids , heme , biochemistry , nitrate reductase , activator (genetics) , intracellular , reductase , lysis , hemeprotein , biophysics , enzyme , biology , nitrate , receptor , organic chemistry , membrane
Several heme proteins including hemoglobin and nitric oxide synthase (NOS) have been documented to serve as nitrite reductase under anoxia. Since sGC is also a heme protein and an important signaling biomolecule, we hypothesized that it may function as nitrite reductase in cultured smooth muscle cells. Millimolar levels of nitrite were required to detect cellular NO as measured by NO specific fluorescent dye (CuFL2E). However, in chemiluminescence analysis of cell lysates, addition of 400–600 μM NO 2 − was sufficient to detect measurable NO formation under anoxic conditions. This NO formation was inhibited with ODQ showing sGC in the cell lysate as the source of nitrite reduction. CO is a known activator of sGC and thus CO donor (50 μM CORM‐2) significantly activated nitrite reduction to NO. The cellular uptake of NO 2 − was studied using the AE‐1 inhibitor, DIDS and intracellular NO 2 − was measured by tri‐iodide assay. DIDS (300 μM) significantly inhibited NO 2 − uptake and showing that NO 2 − uses AE‐1 transport mechanism. These results demonstrate that sGC mediates NO 2 − reduction to form NO and that the AE‐1 channel is one of the pathways for NO 2 − entry into SMC. This work was supported by NIH grant SC1HL095101 .