The unusual active site of Gal6/bleomycin hydrolase can act as a carboxypeptidase, aminopeptidase, and peptide ligase.
Zheng, W., Johnston, S.A., Joshua-Tor, L.(1998) Cell 93: 103-109
- PubMed: 9546396 
- DOI: 10.1016/s0092-8674(00)81150-2
- Primary Citation of Related Structures:  
1A6R, 3GCB - PubMed Abstract: 
The Gal6 protease is in a class of cysteine peptidases identified by their ability to inactivate the anti-cancer drug bleomycin. The protein forms a barrel structure with the active sites embedded in a channel as in the proteasome. In Gal6 the C termini lie in the active site clefts ...