PHASE RELATIONSHIP IN PHENOL-INSULIN CRYSTAL-GROWTH SYSTEM

Based on the crystal growth system of rhombohedral 2Zn-insulin, the ph ase transition of insulin crystals has been investigated with the phen ol concentration as an independent component. The diagram of the phase relationship in this crystal growth system was established, and two p oints of phase transition were found. The transition point I indicates the phase transition between rhombohedral 2Zn-insulin crystal and rho mbohedral 4Zn-insulin crystal, and these two phases coexist within a n arrow region of phenol concentration (0.028%-0.029% (g/ml)). Point II at 0.76%-0.77% (g/ml) of phenol concentration shows the phase transiti on between rhombohedral crystal and monoclinic crystals, and a new pha se of monoclinic crystal (B-form monoclinic insulin crystal) has been observed. This paper reports the diagram of phase relationship obtaine d from our experiments, and analyses and discusses the dependence of p hase transition of insulin crystals on phenol concentration in crystal growth system.