Formation of transaminase-PLP Schiff base.

Imine formation is one of those mechanisms you may have blown past in your organic course, but which has a high level of importance for the MCAT because of its importance within biochemistry. A recurring motif in metabolism is the formation of a Schiff base (imine) between an aldehyde or ketone substrate and an enzyme lysine. Among many enzyme mechanisms, you see this step is part of the mechanism in aldolase in glycolysis and transketolase in the pentose phosphate pathway. Another prominent example is Schiff base formation between pyridoxal phosphate (PLP) and the alpha amine group of amino acids in many enzymes involved in amino acid breakdown or synthesis.