[dnautics]

Good luck. When you make an imine with an aldehyde the principal mechanism of irreversability is that a stray reductant (available in spades in biochemical settings) takes the imine down to a primary amine. (This is not found in most textbooks, you just have to know that). Now, a primary amine is a relatively stable covalent bond, and getting selective deamination is going to be especially difficult since there's plenty of amines around. Not the least of which is the other side of the lysine that the aldehyde attached to in the first place.