Assay of human platelet guanylate cyclase activity by high-performance liquid chromatography with fluorescence derivatization

A selective and sensitive high-performance liquid chromatography (HPLC) met hod with fluorescence derivatization for the assay of guanylate cyclase (GC ) activity is described. GTP and cGMP, which are the substrate and the prod uct of GC, respectively, and other guanine-containing compounds are selecti vely converted by the reaction with (3,4-dimethoxyphenyl)glyoxal to the flu orescent derivatives. The derivatives were separated by reversed-phase HPLC . The limit of detection at a signal-to-noise ratio of 3 for cGMP was 10 fm ol on the column. The sensitivity of this method was less than that of the conventional radioisotopic method, but this method is simple and convenient . Human platelet GC activity was measured, and the effects of some compound s were investigated. (C) 2001 Elsevier Science BN. All rights reserved.