TNP-GTP tetrasodium is a fluorescently labeled GTP (HY-113225) derivative. TNP-GTP tetrasodium can inhibit glutamate dehydrogenase (Ki = 2.7 µM). TNP-GTP tetrasodium is an antagonist of the purinergic P2X2 and P2X2/3 receptors with IC50 values of 0.4 and 1.2 nM, respectively. TNP-GTP tetrasodium also inhibit rat soluble guanylyl cyclase (Ki = 11 nM)[1][2][3].