Crystallization of a multienzyme complex: fatty acid synthetase from yeast.

The crystallization of purified fatty acid synthetase from yeast is facilitated by seeding techniques. The first seed crystals appeared as particles with almost negligible enzymatic activity in a solution that had been left at 4 degrees C for 15 months. Subsequently, the crystallization time has been reduced to two days, and the crystals now isolated have retained their full enzymatic activity. The loss of synthetase activity that can result from prolonged exposure during crystallization is attributable specifically to damage of the enzyme component responsible for condensation activity. Crystalline synthetase is identical to purified but noncrystalline synthetase by all criteria so far examined.