The initial stages in the purification of pig liver esterase

Abstract

Well minced pig-liver was suspended in twice its wt. of water (containing 5 ml. toluene/1.) and stirred for 1 hr. and strained. The suspension was adjusted to pH 5.7 (point of minimum solubility for esterase) and the insoluble materials collected and washed twice by suspending in water and recovering in a "super centrifuge." The esterase was eluted at pH 9.5 (point of maximum solubility) in cold, and the eluted enzyme precipitated at pH 6.0 with 0.1 N HCl. A product was obtained which contained 40% of original esterase and was 10-15 times richer than the liver. The existence of 2 esterases was demonstrated by solubility in (NH4)2SO4 solns. Drying of the washed bound esterase, with acetone and ether resulted in complete loss of activity.