Abstract
We have developed a new method for protein crystallization, crystal hysteresis, that utilizes slow-cooling and recooling techniques. Slow cooling of a saturated solution enables precise control of supersaturation in the solution and also allows reuse of the solution because it maintains its composition. Examination of the effects of various cooling rates on hen egg-white lysozyme crystallization revealed that the cooling rate determined the number and size of the obtained crystals. Furthermore, recrystallization of lysozyme from the same solution after dissolving the previously grown crystals was found to be very effective in reducing the number of nucleation sites, thus obtaining larger crystals.