First natural Diels–Alder enzyme discovered in mulberry tree

The first enzyme that catalyses Diels–Alder reactions has been found in mulberry plants by an international team of scientists.¹ Unlike other enzymes that have been labelled Diels–Alderases, this is the only one that promotes truly concerted intermolecular [4+2] cycloadditions – and it does so better than most synthetic catalysts.