The degradation of canavanine by jack bean cotyledons

Abstract

Germinating jack bean cotyledons liberated ¹⁴CO₂ when fed ¹⁴C-guanidoxy-canavanine but did not accumulate any ¹⁴C-compounds other than the applied canavanine. This suggested that the canavanine was being degraded by the action of canavanase to canaline and urea, the urea then being converted to ammonia and carbon dioxide by the action of urease. Hydroxyurea and acetohydroxamic acid (both inhibitors of urease activity) strongly inhibited the liberation of ¹⁴CO₂ from ¹⁴C-guanidoxy-canavanine by the cotyledons but neither compound induced the accumulation of ¹⁴C-urea within the tissues. This inhibitory action of hydroxyurea on ¹⁴CO₂ output was thought to be due at least in part, to this inhibition of canavanase activity.