Abstract
A newly discovered enzyme, L-canaline reductase (NADPH:L-canaline oxidoreductase, EC 1.6.6-), has been isolated and purified from 10-day-old leaves of the jack bean Canavalia ensiformis (Leguminosae). This higher plant is representative of a large number of legumes that synthesize L-canavanine, an important nitrogen-storing nonprotein amino acid. Canavanine-storing legumes contain arginase, which hydrolyzes L-canavanine to form the toxic metabolite L-canaline. Canaline reductase, having a mass of approximately 167 kDa and composed of 82-kDa dimers, catalyzes a NADPH-dependent reductive cleavage of L-canaline to L-homoserine and ammonia. This is the only enzyme known to use reduced NADP to cleave an O-N bond. Canaline reductase performs at least three important functions for canavanine-synthesizing legumes. First, it detoxifies canaline. Second, it increases by one-half the overall yield of ammoniacal nitrogen released from canavanine. Third, it permits the carbon skeleton of canavanine, a secondary plant metabolite, to support vital primary metabolic reactions.
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Selected References
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- Beeler T., Churchich J. E. Reactivity of the phosphopyridoxal groups of cystathionase. J Biol Chem. 1976 Sep 10;251(17):5267–5271. [PubMed] [Google Scholar]
- DAVIS B. J. DISC ELECTROPHORESIS. II. METHOD AND APPLICATION TO HUMAN SERUM PROTEINS. Ann N Y Acad Sci. 1964 Dec 28;121:404–427. doi: 10.1111/j.1749-6632.1964.tb14213.x. [DOI] [PubMed] [Google Scholar]
- Fournier D., Bergé J. B., Cardoso de Almeida M. L., Bordier C. Acetylcholinesterases from Musca domestica and Drosophila melanogaster brain are linked to membranes by a glycophospholipid anchor sensitive to an endogenous phospholipase. J Neurochem. 1988 Apr;50(4):1158–1163. doi: 10.1111/j.1471-4159.1988.tb10587.x. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Rosenthal G. A. A mechanism of L-canaline toxicity. Eur J Biochem. 1981 Feb;114(2):301–304. doi: 10.1111/j.1432-1033.1981.tb05149.x. [DOI] [PubMed] [Google Scholar]
- Rosenthal G. A., Dahlman D. L. Interaction of L-canaline with ornithine aminotransferase of the tobacco hornworm, Manduca sexta (Sphingidae). J Biol Chem. 1990 Jan 15;265(2):868–873. [PubMed] [Google Scholar]
- Rosenthal G. A., Dahlman D. L., Janzen D. H. A novel means for dealing with L-canavanine, a toxic metabolite. Science. 1976 Apr 16;192(4236):256–258. doi: 10.1126/science.1257764. [DOI] [PubMed] [Google Scholar]
- Rosenthal G. A., Dahlman D. L., Robinson G. W. L-Arginine kinase from tobacco hornworm, Manduca sexta (L.). Purification, properties, and interaction with L-canavanine. J Biol Chem. 1977 Jun 10;252(11):3679–3683. [PubMed] [Google Scholar]
- Rosenthal G. A. Investigations of Canavanine Biochemistry in the Jack Bean Plant, Canavalia ensiformia (L.) DC: I. Canavanine Utilization in the Developing Plant. Plant Physiol. 1970 Aug;46(2):273–276. doi: 10.1104/pp.46.2.273. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rosenthal G. A. Preparation and colorimetric analysis of L-canavanine. Anal Biochem. 1977 Jan;77(1):147–151. doi: 10.1016/0003-2697(77)90299-8. [DOI] [PubMed] [Google Scholar]
- Rosenthal G. A. The preparation and colorimetric analysis of L-canaline. Anal Biochem. 1973 Feb;51(2):354–361. doi: 10.1016/0003-2697(73)90488-0. [DOI] [PubMed] [Google Scholar]
- Rosenthal G. A., Thomas D. Radiochemical synthesis of DL-canaline and the colorimetric assay of canaline. Anal Biochem. 1984 Jul;140(1):246–249. doi: 10.1016/0003-2697(84)90160-x. [DOI] [PubMed] [Google Scholar]
- Rosenthal G., Dahlman D. L. Non-protein amino acid-insect interactions-II. Effects of canaline-urea cycle amino acids on growth and development of the tobacco hornworm, Manduca sexta L. (Sphingidae). Comp Biochem Physiol A Comp Physiol. 1975 Sep 1;52(1):105–108. doi: 10.1016/s0300-9629(75)80138-1. [DOI] [PubMed] [Google Scholar]