Lysine-69 plays a key role in catalysis by ornithine decarboxylase through acceleration of the Schiff base formation, decarboxylation, and product release steps

Research was conducted to examine the mechanistic role of the Lys-69 residue in catalysis by Trypanosoma brucei ornithine decarboxylase (ODC) via an analysis of the mutant enzymes. It was found that the enzyme copurified with amines hat were tightly bound to the active site through a Schiff base with pyridoxal-5'-phosphate-dependent. A kinetic analysis of the binding of a series of diamines and amino acids to Arg ODC indicates that noncovalent interactions in the active site of Arg ODC promote selective ligand biding during Schiff base formation.