The enzyme has been characterized from the bacterium?Mycobacterium tuberculosis. It catalyses the hydrolysis of the amido group of the C-terminal glutamine of prokaryotic ubiquitin-like protein (Pup), thus activating it for ligation to target proteins, a process catalysed by EC?6.3.1.19, prokaryotic ubiquitin-like protein ligase. Deamination requires ATP as cofactor but not its hydrolysis. The enzyme also catalyses the hydrolytic cleavage of the bond formed by the ligase, between an ¦Å-amino group of a lysine residue of the target protein and the ¦Ã-carboxylate of the C-terminal glutamate of the prokaryotic ubiquitin-like protein.
