Specific detection of kappa light chain in uric acid stones

Proteins were extracted from uric acid stones with 6M guanidine chloride (pH 8.5), which were successively developed by 12% polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE). Amino acid sequence analysis of each band on SDS-PAGE revealed that major components in uric acid stones were immunoglobulin alpha heavy and kappa light chains. Although immunoglobulin heavy chain (gamma and mu, as well as alpha) and a kappa light chain were clearly detected in uric acid stones by Western blotting using their specific antibodies, no lambda chains whatsoever could be detected. The results suggest that immunoglobulins selectively containing kappa light chain might have specific functions in uric acid stone formation as stone matrices.