1998/04/01 by Wanda L.B. White, Diana I. Arias-Garzon, Jennifer M. McMahon +1 · 161 citations
Agricultural and Biological Sciences · Chemistry · Environmental Science · #Acetone #Biochemistry #Biology #Botany #Cassava research and cyanide #Catalysis #Chemistry #Cyanide #Cyanohydrin #Enzyme #Food science #Isotope Analysis in Ecology #Manihot #Manihot esculenta #Organic chemistry
paper · open access · doi:10.1104/pp.116.4.1219
published in PLANT PHYSIOLOGY 116(4), 1219-1225 (Oxford University Press)
openalex publication_date 1998/04/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/15
In the cyanogenic crop cassava (Manihot esculenta, Crantz), the final step in cyanide production is the conversion of acetone cyanohydrin, the deglycosylation product of linamarin, to cyanide plus acetone. This process occurs spontaneously at pH greater than 5. 0 or enzymatically and is catalyzed by hydroxynitrile lyase (HNL). Recently, it has been demonstrated that acetone cyanohydrin is present in poorly processed cassava root food products. Since it has generally been assumed that HNL is present in all cassava tissues, we reinvestigated the enzymatic properties and tissue-specific distribution of HNL in cassava. We report the development of a rapid two-step purification protocol for cassava HNL, which yields an enzyme that is catalytically more efficient than previously reported (Hughes, J., Carvalho, F., and Hughes, M. [1994] Arch Biochem Biophys 311: 496-502). Analyses of the distribution of HNL activity and protein indicate that the accumulation of acetone cyanohydrin in roots is due to the absence of HNL, not to inhibition of the enzyme. Furthermore, the absence of HNL in roots and stems is associated with very low steady-state HNL transcript levels. It is proposed that the lack of HNL in cassava roots accounts for the high acetone cyanohydrin levels in poorly processed cassava food products.