REFINED 1.8-ANGSTROM RESOLUTION CRYSTAL-STRUCTURE OF THE PORCINE EPSILON-TRYPSIN

Porcine epsilon-trypsin is a three-chain inactivated trypsin from the limited autolysis of porcine beta-trypsin. It is cleaved at positions Lys(60)-Ser(61) and Lys(145)-Ser(146). The crystal structure has been determined by using the molecular replacement method, and refined at 1 .8 Angstrom resolution. The R-value of final model is 0.184. Compariso n with the electron density map of porcine beta-trypsin (PTRY) in comp lex (BBIT), and with that of native bovine beta-trypsin (HTNA), reveal ed no obvious changes except at the autolysis positions, and no change s at the active center were observed. The autolysis at positions Lys(6 0)-Ser(61) and Lys(145)-Ser(146) does not affect the conformation of H is-57 in the active center and therefore cannot explain for a loss in porcine epsilon-trypsin activity.