Provided are antibodies that bind to: a sulfonated epitope of the protein Sclerostin, to Sclerostin portions comprising a sulfonated amino acid and to dimerized forms of Sclerostin. Further provided are compositions and peptides comprising a sulfonated epitope of sclerostin. Also provided by this invention are methods for production of such antibodies, both active and passive, and methods for identifying antibodies specific for sulfonation sites in Sclerostin and other antibodies which discriminate between sulfonated and unsulfonated forms of sclerostin. Physical and virtual screening processes are provided in this invention for identifying compounds which disrupt or inhibit sulfonation and the interaction between Sclerostin and binding partners. The antibodies and compositions of the present invention are useful in diagnostic and therapeutic applications directed to Sclerostin-related disorders.