PROTEIN-BINDING TO MONOSODIUM URATE MONOHYDRATE, CALCIUM PYROPHOSPHATE DIHYDRATE, AND SILICON DIOXIDE CRYSTALS .1. PHYSICAL CHARACTERISTICS

Google Scholar
  • 1 January 1977
    • journal article
    • research article
    • Vol. 89  (6) , 1314-1325
Abstract
The protein adsorptive properties of monosodium urate monohydrate (MSU), silica (Si) and calcium pyrophosphate dihydrate crystals were studied by qualitative and quantitative techniques. Immunoglobulin G (IgG) was adsorbed preferentially by MSU crystals from normal human serum and demonstrated high-affinity binding isotherms when compared with several isolated proteins in solution. The physical characteristics of this reaction suggest principally an ionic mechanism, since adsorption was enhanced by decreasing pH or ionic strength. Weaker physical forces also were suggested by studies showing enhanced adsorption at lower temperatures. The following order of affinity for Si or MSU crystals was found when equal concentrations of proteins were compared: Cohn fraction II > lysozyme > .beta. lactoglobulin > bovine serum albumin > ovalbumin. IgG adsorption to the crystals studied may explain certain features of their biological activity. This phenomenon probably blocks the membranolytic properties of crystals and stimulates their phagocytosis through interaction with Fc receptors on the surface of the phagocytic cells.