L-Canaline Detoxification: A Seed Predator's Biochemical Mechanism

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Science  03 Nov 1978:
Vol. 202, Issue 4367, pp. 528-529
DOI: 10.1126/science.202.4367.528


The seeds of the Neotropical legume, Dioclea megacarpa, the sole food source for developing larvae of the bruchid beetle, Caryedes brasiliensis, contain about 13 percent L-canavanine (dry weight). Canavanine detoxification and utilization produces L-canaline, a potent neurotoxic and insecticidal amino acid. This seed predator has developed a unique biochemical mechanism for degrading canaline by reductive deamination to form homoserine and ammonia. In this way, canaline is detoxified; canavanine's stored nitrogen is more fully utilized and its carbon skeleton is conserved.