GROWTH-MECHANISM OF CONCANAVALIN-A CRYSTALS

Crystals of concanavalin A were obtained in four different morphologie s, depending on protein and precipitant (NaNO3) concentration, tempera ture and pH. The morphologies were round, round rhombic tetrahedron, s mooth faceted and well faceted. The growth rate and the rate limiting step of the rounded concanavalin A crystals were investigated. The gro wth rate as a function of the supersaturation is compared with models obtained from studies of small molecule crystals. The most probable gr owth mechanism for these round crystals is found to be the rough surfa ce growth mechanism. This was confined with electron microscopy. The t ime when crystal growth ceases was determined and found to be independ ent of the precipitant concentration.