Plant extracts from a variety of plant tissues were screened for hydro
xynitrile lyase activity using a screening assay based on the conversi
on of mandelonitrile to benzaldehyde and HCN. Many plants extracts wer
e discovered that catalysed the cleavage of mandelonitrile but not the
synthesis reaction. In further investigations one esterase (from Pseu
domonas marginata) with this activity was found.