In one embodiment, the language ???substantially free of chemical precursors or other chemicals??? includes preparations of Lor-2 protein having less than about 30% (by dry weight) of chemical precursors or non-Lor-2 chemicals, more preferably less than about 20% chemical precursors or non-Lor-2 chemicals, still more preferably less than about 10% chemical precursors or non-Lor-2 chemicals, and mo