1PYT:
reference: The three-dimensional structure of the native ternary complex of bovine pancreatic procarboxypeptidase A with proproteinase E and chymotrypsinogen C., Gomis-Ruth FX, Gomez M, Bode W, Huber R, Aviles FX, EMBO J 1995 Sep 15;14(18):4387-94. PMID: 7556081

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).