Two-dimensional electrophoretic analyses of urinary proteins in Chinese male urinary stone patients

This study was aimed to detect the differences in soluble urinary proteins between normal Chinese male individuals and urinary stone formers by 2-dimensional electrophoresis. Twenty urine samples were obtained from normal male adults and 35 from recurrent male urinary stone formers. The stone compositions included calcium oxalate, uric acid, carbonate apatite, and brushite. Two hundred milliliters of fresh urine was collected for analysis. Each urine sample was concentrated, dialyzed, frozen and lyophilized. The samples of the same stone composition were pooled and subjected to two-dimensional electrophoresis. Comparison of protein profiles between normal individuals and stone formers revealed a number of proteins which are not present in the urine of normal individuals, 5 from calcium oxalate, 2 from uric acid, 3 from carbonate apatite and 2 from brushite. These urinary stone-associated proteins comprise proteins A (37kd), B (30kd), C (26kd), D (25kd), and E (22kd) for calcium oxalate, proteins F (63kd) and G (59kd) for uric acid, protein H (65kd), I (42kd), and J (30kd) for carbonate apatite as well as proteins K (61kd) and L (59kd) for brushite. Among them, the proteins A, I, and J exhibited charge heterogeneity.