Characterization of a novel monoclonal antibody that senses nitric oxide-dependent activation of soluble guanylate cyclase.

Two monoclonal antibodies (mAbs) against bovine lung soluble guanylate cyclase (sGC) were prepared and characterized. mAb 3221 recognized both the alpha- and beta-subunits of sGC and had greater binding affinity to the enzyme in the presence of NO. mAb 28131 recognized only the beta-subunit and its affinity did not change with NO. Neither mAb cross-reacted with particulate GC. Cultured Purkinje cells from rats were treated with S-nitroso-N-acetylpenicillamine, an NO donor, and examined by immunocytochemical methods. The immunoreactivity associated with mAb 3221 increased with the cGMP content in a crude extract of cerebellum and the NO2 generated in the culture medium increased.