Imine chemistry in plant metabolism

Imine chemistry represents an important category of chemical reactions involved in the biosynthesis plant natural products, ranging from newly discovered mobile defense hormone N-hydroxy-pipecolic acid to red-to-yellow tyrosine-derived betalain pigments. Spontaneous imine formation have also served as basis for evolution numerous metabolic enzymes, such specialized Pictet-Spenglerases that produce backbone structures benzylisoquinoline and monoterpene indole alkaloids pyridoxal 5′-phosphate-dependent enzymes diverse functions. Here, we review occurrences metabolism their biochemical mechanisms. A better understanding will ultimately facilitate synthetic biology approaches further expand scope product broad biotechnological applications.