properties of matter : Freeze-dried powder. Porcine Pancreas Lyophilized powder.. The enzyme should be 0.22 micron filtered after reconstitution and prior to use. Suitable for the isolation of Type II lung cells. Unit Definition:One unit cleaves one micromole of N-succinyl-L-alanyl-L-alanyl-L-alanine-p-nitroanilide per minute at 25°C, pH8.0.