Temperature is being recognized as a noninvasive control parameter for protein crystallization. Before temperature-induced crystallization can be routinely used as a method of preparation of protein crystals, qualitative data on the temperature dependent solubility of the protein must be obtained. Qualitative data for tt temperature-dependent solubility is available for a limited number of proteins. We report herein qualitative temperature-dependent solubility data for selected proteins as obtained by the use of a multichambered thermal gradient device. These studies demonstrate that a large percentage of proteins do in fact exhibit a solubility versus temperature dependence which suggests that temperature can be used as an alternative crystallization technique for proteins. (C) 1998 Elsevier Science B.V. All rights reserved.