Isolation From Human Calcium Oxalate Renal Stones of Nephrocalcin, a Glycoprotein Inhibitor of Calcium Oxalate Crystal Growth. Evidence That Nephrocalcin From Patients With Calcium Oxalate Nephrolithiasis is Deficient in γ-Carboxyglutamic Acid

We have determined that the organic matrix of calcium oxalate kidney stones contains a glycoprotein inhibitor ofcalcium oxalate crystal growth (nephrocalcin) that resembles nephrocalcin present in the urine of patients with calcium oxalate stones and differs from nephrocalcin from the urine of normal people. Pulverized calcium oxalate renal stones were extracted with 0.05M EDTA, pH 8.0; nephrocalcin eluted in five peaks using DEAE-cellulose column chromatography, and each peak was further resolved by Sephacryl S-200 column chromatography. Four ofthe fiveDEAE peaks corresponded to those usually found in nephrocalcin from urine; the fifth eluted at a lower ionic strength than any found in uri…