The use of immobilized methylchymotrypsin for the purification of human and sheep alpha-1-proteinase inhibitor (alpha(1)-PI).

alpha(1)-proteinase inhibitor was isolated from albumin fractions of human and sheep plasma using a new method of purification using affinity chromatography on immobilized methylchymotrypsin in the presence of 5 M NaCl. The inhibitor was finally polished to homogenity either by chromatography on a Mono Q or a Sephacryl S-200 HR column. The presented method makes it possible to recover alpha(1)-proteinase inhibitor which has been added to cow milk.