sentences:  A possible candidate for the base in the mechanism could be Lys280 that was just pushed off of PLP, which sequesters the newly formed amino group of the PLP-TYR molecule.In a similar mechanism of aspartate transaminase, the lysine that forms the initial imine to PLP later acts as the base that attacks the tyrosine in transimination.The electrons left behind from the loss of the proton move down to form a new double bond to the imine, which in turn pushes the already double bonded electrons through PLP and end up as a lone pair on the positively charged nitrogen in the six-membered ring of the molecule.