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

Abstract

Uniformly labelled L-valine-¹⁴C and L-isoleucine-¹⁴C 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-¹⁴C isolated from the tops of etiolated seedlings of these species which had been fed H¹⁴CN 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-¹⁴C, the occurrence and distribution of radioactivity in asparagine-¹⁴C suggests that radioactive linamarin formed from the valine breaks down slowly to yield H¹⁴CN which in turn is incorporated into asparagine.