Cyanamide is biosynthesized from L-canavanine in plants

Cyanamide had long been recognized as a synthetic compound but more recently has been found as a natural product from several leguminous plants. This compound's biosynthetic pathway, as yet unelaborated, has attracted attention because of its utility in many domains, such as agriculture, chemistry, and medicine. We noticed that the distribution of L-canavanine in the plant kingdom appeared to include that of cyanamide and that the guanidino group structure in L-canavanine contained the cyanamide skeleton. Here, quantification of these compounds in Vicia species suggested that cyanamide was biosynthesized from L-canavanine. Subsequent experiments involving L-[guanidineimino-(15)N2]canavanine addition to young Vicia villosa seedlings resulted in significant incorporation of (15)N-label into cyanamide, verifying its presumed biosynthetic pathway.