Monoclonal antibody identification of a potentially lithogenic protein extracted from human renal calculi

In an attempt to identify potentially lithogenic proteins, a detergent soluble extract of human renal calculi was used to produce a unique monoclonal antibody. The monoclonal antibody was found to detect the presence of a specific epitope in 77% of individually extracted kidney stones from our patients' stone bank at The Long Island Kidney Stone Unit, State University of New York, Stony Brook. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoprecipitation, and Western Blot analysis revealed this monoclonal antibody to be specific to a protein of 83,000 dalton molecular weight. A secondary source of protein reactive to the monoclonal antibody was subjected to enzyme kinetic studies, those studies suggested that the 83,000 dalton protein is a member of the protein-glutamine gammaglutamyltransferase (transglutaminase) family of enzymes. It was not determined in the present investigation whether a member of this family of enzymes initiates or is necessary for lithiasis.