If we survey the literature on the crystallization of aldolases we find that ammonium sulfate and phosphate are commonly used. In fact this has enabled us to use Tungstate as a heavy atom derivative. FIV dUTPase Two crystal forms of FIV dUTPase were obtained using ammonium sulfate. Cacodylate is a phosphate mimic. Crystallization is inhibited by adding phosphate to the mother liquor.
Crystals dissolve when vanadate, molybdate and tungstate are added.
We have observed different crystal forms with Lithium sulfate additions to the crystallization in polyethylene glycol. Magnesium dependence is typical in enzymes that bind tri-phosphates. Zinc is often an inhibitor of this reaction. On the other hand zinc is required for activity in alkaline phosphatase. Hence, in many cases it is important to investigate various divalent metals as additives .