Abstract:

Mimic (artificial) urine soln. of 10-3M Ca2+ concn. was mixed with equimolar Na oxalate soln. and the Ca2+ concn. (activity) was measured. The Ca2+ concn. rapidly decreased as a result of Ca oxalate pptn., reaching a plateau after 30 min. Addn. of polyglutamate or polyaspartate retarded the drop in the Ca2+ concn. Glutamate or aspartate (monomer) and glutamylglutamic acid (dimer) had no retardation effect. Three other polymers with free carboxylic or sulfonic groups (PAS, PAA, CMC) inhibited Ca2+ pptn. in a similar way to polyglutamate, whereas albumins and polyethyleneglycol had no effect. Addn. of 5-10% normal urine retarded Ca2+ pptn., whereas 10% pathol. urine had no effect. [on SciFinder(R)]