[Purification of an anionic trypsin from the gastric juice of the crayfish Cambarus affinis say by means of affinity chromatography].

Beside other digestion enzymes the crayfish Cambarus affinis SAY possess an anionic trypsin. This enzyme could be separated from all the other proteins of the crude gastric juice by a single affinity chromatographic step on immobilized natural inhibitor. The dissociation of the thus produced enzyme-inhibitor complex was achieved by specific elution with ben-amidine. The soluble benzamidine-trypsin-complex was dialyzed and separated by gelfiltration on Sephadex G-50. Of the ligands used Trasylol proved to be the most effective one. Trypsin isolated by this ligand was in a discelectrophoretic homogeneous state. On the other hand, trypsin purified by Soybean trypsin inhibitor and Contrykal contains impurities.