Inhibitory effect of glutamic acid and aspartic acid on calcium oxalate crystal formation.

The effects of Glu and Asp on calcium stone formation was evaluated in three experiments. Studies using mixed suspension, mixed product removal crystallization and scanning electron microscopy showed that Glu and Asp inhibited the nucleation rate, growth rate and suspension density (crystal mass produced) in proportion to the concentration. The main amino acids in calcium oxalate stones and calcium phosphate stones were Glu and Asp. However, the main amino acids in uric acid stones were glycine and urea, and there were no specific amino acids in struvite stones. The activity of urinary GOT and GPT, which convert Asp and alanine, respectively, to Glu in normal subjects was significantly greater than in calcium stone formation.