Serum antibodies that distinguish between the phospho- and dephospho-forms of a phosphoprotein

Abstract

Considerable evidence suggests that the actions of many hormones, neurotransmitters, neuromodulators and oncogenic viruses are mediated through regulation of the state of phos-phorylation of specific proteins1,2. Many such phosphoproteins have been found, which serve as specific substrates for various classes of protein kinases1,2. We report here the successful preparation of antibodies which are selective for either the dephospho- or the phospho-form of one such phosphoprotein. Thus, we have prepared both dephospho-selective and phospho-selective serum antibodies to G-substrate3,4, a neurone-specific substrate for cyclic GMP-dependent protein kinase, and have used them as the basis of a radioimmunoassay procedure for studying the state of phosphorylation of this protein. © 1982 Nature Publishing Group.