Abstract: An aspartic acid rich protein isolated from human urine, as well as proteins having substantial homology thereto and active portions of the foregoing are effective modulators of mineralization in mammals. These proteins and peptides are useful as therapeutic agents, such as in the treatment of kidney stone disease. Hybridoma cell lines capable of producing monoclonal antibodies to these proteins and peptides and monoclonal antibodies produced by these hybridomas are disclosed. These monoclonal antibodies are also useful as therapeutic agents, such as in the treatment of osteoporosis, and further have utility as diagnostic agents. Other uses are also described.