ELSEVIER LifeSciences, Vol.61,No.3,pp.249.2.53, 1997 C%W@t01997El*~er science Inc. Printed intheUSA.Allrights reserved 0034-3205/97 $17.00+ .00 PII S0024-3205(97)00380-9 SPECIFIC DETECTION OF K LIGHT CHAIN IN URIC ACID STONES YoshihiroHashimoto’,KenjiroKohril,Yutaro I-Iayashil, AkihikoMoriyama’,Masanon Iguchi’,KiyofurniAsai2and Taiji Kato2 ‘Department of Urology,‘Department of BioregulationResearch, ‘Institute of Natural Sciences,Department of LifeScience,Laboratory of Biomolecuku- Science,Nagoya City University MedicalSchool, l-Kawasumi,Mizuho-cho,Mizuho-ku,Nagoya467Japan ‘Department of Urology,KinkiUniversity Schoolof Medicine, 377-2Onohigashi,Osakasayama-shi,Osaka589Japan (Received in fmafform April 9, 1997) Summary 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 a heavy and ~ light chains. Although immunoglobulin heavy chain ( Y and L, as well as a ) and a IKlight chain were clearly detected in uric acid stones by Western blotting using their specific antibodies, no A chains whatsoever could be detected. The results suggest that immunoglobulinsselectively containing ~ light chain might have specificfunctions in uric acid stone formationas stone matrices. Key Words: uric acid stone, immunogfobufins, K light chain Urinary stones comprise a crystalline or mineral phase and a non-crystalline or organic phase. The latter component, a proteinaceous moiety, is known as a urinary stone matrix. Organic matrix of urinary stone accounts for 2-3%of the total stone weight, and consists mainly of a mixture of proteins, carbohydrates, glycosaminoglycanes, lipids and organic ash (l-5).By immunological techniques, Tamm Horsfall glycoprotein, albumin and transferringhave been found (6,7).We have characterized osteopontin and calprotectin as a calcium binding protein in the calcium-containing stones, calcium oxalate or calcium phosphate (8,9).However,the protein matrix in the calcium-free stones such as uric acid stone and cystine stone has not been found.In this study we have, for the first time, demonstrated stone proteins in uric acid stones and identified the immunoglobulinheavy and light chains as major co-precipitatingmatrix proteins. CorrespondingAuthon YoshihiroHashimoto, Department of Urology,Nagoya City University MedicalSchool, l-Kawasumi,Mizuho-cho,Mizuhmku,Nagoya467,Japan. PHONB +81-52-851-5511 FAX +81-52-852-3179