Introduction - This script shows the structural differences between trypsin and its zymogen trypsinogen [Based on 1tgb.pdb - H. Fehlhammer, W. Bode, R. Huber, J.Mol.Biol. 111 415 (1977) and 3ptn.pdb - J.Walter,W.Steigemann,TP.Singh,H.Bartunik,W.Bode, R.Huber Acta Crystallor., Sect.B, 38 1462 (1982)).
Trypsin and trypsinogen have very similar overall tertiary structures.
This view shows that the catalytic triad has essentially the same structure in the zymogen and active enzyme.
Likewise, the specificity pocket seems very similar in trypsinogen and trypsin.
However, the oxyanion hole of trypsin, which involves two backbone nitrogens is not properly formed in trypsinogen. Recall that the oxyanion hole stablizes the transition state.