Studies on cyanide metabolism in Lotus arabicus L. and Lotus tenuis L.

Abstract Uniformly labelled L -valine- 14 C and L -isoleucine- 14 C serve respectively as effective precursors of the aglycone moieties of the two cyanogenic glucosides, linamarin (α-hydroxy-isobutyronitrile-β- D -glucose and lotaustralin (α-hydroxy-α-methylbutyronitrile-β- D -glucose) which occur in Lotus arabicus L. and Lotus tenuis L. Asparagine- 14 C isolated from the tops of etiolated seedlings of these species which had been fed H 14 CN was degraded and the data obtained provide evidence for the amide carbon atom being formed from the nitrile carbon. In the case of plants fed L -valine-U- 14 C, the occurrence and distribution of radioactivity in asparagine- 14 C suggests that radioactive linamarin formed from the valine breaks down slowly to yield H 14 CN which in turn is incorporated into asparagine.