The Effects Of Amino Acids On The Growth Of Calcium Oxalate Crystal

The effects of various kinds of amino acids and pH of solution on the crystallization of CaOxa were investigated in aqueous solution by means of X-ray power diffraction (XRD) and Scanning electronic microscope(SEM).The effects of amino acids on the crystallization of calcium oxalate monohydrate (COM) resulted from electrostatic attraction of amino acids with the crystals. Acidic amino acids such as glutamic acid and asparatic acid inhibited the nucleation of COM and promoted its growth and aggregation. Neutral amino acid (phenlalanine) inhibited the growth of COM in the concentration range from 0.01 to 0.1 mmol/L and inhibited its nucleation in the range from 0.1 to 1 mmol/L. Basic amino acid (hisditine) inhibited the nucleation of COM in the concentration range from 0.01 to 0.1 mmol/L and promoted the nucleation in the range from 0.1 to 1 mmol/L.The effects of pH on the number, morphology and crystal faces of CaOxa were dicussed in pH experiments. The higher pH values, the more CaOxa crystal produced; when pH of the solutions was higher than isoelectric points (pI) of amino acids, CaOxa crystal growth paralleled with ((?)01) face of COM; when pH of solution was high, slice COM crystal produced in solution in which lysine was added.