A comparative study of arginase and canavanase

Damodaran, M.; Narayanan, K.

doi:10.1042/bj0341449

Cited by 76 publications

(23 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

mentioning

confidence: 99%

“…Attempts have been made to isolate an enzyme responsible for the formation of one of the intermediates of canavanine metabolism that is distinct from its ornithine-urea cycle counterpart. These efforts have failed (3,9).One can readily demonstrate all of the ornithine-urea cycle enzymes in jack bean, except for argininosuccinic acid synthetase, typically, the rate-limiting enzyme ofthe ornithine-urea cycle (18). The lack of appreciable argininosuccinic acid synthetase activity has prevented unequivocal in vitro demonstration of the role of the ornithine-urea cycle enzymes in canavanine biosynthesis.…”

mentioning

confidence: 99%

“…Its mobilization and utilization injack bean, Canavalia ens!formis (L.) DC. (Leguminosae), occurs via arginase (EC 3.5.3.1), which cleaves L-canavanine to L-canaline and urea (3). Urea is hydrolyzed by urease (EC 3.5.1.5) to CO2 and NH3; the latter, representing an important source of reduced nitrogen, is assimilated and incorporated into the amide nitrogen of asparagine (I 1).…”

mentioning

confidence: 99%

See 2 more Smart Citations

l-Canavanine Metabolism in Jack Bean, Canavalia ensiformis (L.) DC. (Leguminosae)

Rosenthal¹

1982

Plant Physiol.

View full text Add to dashboard Cite

L-Canavanine, a highly toxic arginine antimetabolite, is the principal nonprotein amino acid of many eguminous plants. Labeled-precursor feeding studies, conducted primarily with I'Clcarbamoyl sphate, and utilization of the seedlins of jack bean, Canavalia enuiformis (L.) DC. (Leguminosae), have provided evidence for L-canavanine biosynthesis from L-canaline via O-ureido-L-homoserine. This reaction pathway appears to constitute an important in vivo route ofcanavanine productiol Canavanine cleavage to canaline may represent a degradative phase of canavanine metabolism distinct from the anabolic reactions described above. Thus, while these reactions of canavanine metabolism bear analgy to the mammalian Krebs-Henseleit ornithie-urea cycle, no evidence has been obtained at present for the reutilization of canaline in ureidohonoserine formation.L-Canavanine, a nonprotein amino acid found in at least 500 species of leguminous plants (2), is a potent antimetabolite, due in large measure to its structural analogy to L-arginine. Canavanine's marked insecticidal action, its ability to disrupt many essential biochemical reactions in a wide range of prokaryotic and eukaryotic organisms, and its appreciable storage in such important tissues as the seed are consistent with its allelochemical role in plant defense against phytophagous insects and other herbivores (14).Canavanine is a major nitrogen storage metabolite of the seed, where it can account for 95% or more of the nitrogen found in the free amino acids (15). Its mobilization and utilization injack bean, Canavalia ens!formis (L.) DC. (Leguminosae), occurs via arginase (EC 3.5.3.1), which cleaves L-canavanine to L-canaline and urea (3). Urea is hydrolyzed by urease (EC 3.5.1.5) to CO2 and NH3; the latter, representing an important source of reduced nitrogen, is assimilated and incorporated into the amide nitrogen of asparagine (I 1).Experimental evidence has been obtained in jack bean for carbamylation ofcanaline with carbamoyl phosphate, in a reaction catalyzed by ornithine carbamoyltransferase (EC 2.1.3.3) to yield O-ureido-L-homoserine, a citrulline analog (12). Argininosuccinic acid lyase (EC 4.3.2.1), the enzyme-mediating conversion of Lcanavaninosuccinic acid to L-canavanine and fumaric acid, has been isolated and purified extensively from jack bean seed (16). Of the reactions depicted in Figure 1, it is the reaction fostered by argininosuccinic acid synthetase (EC 6.3 The enzymic reactions of the nonprotein amino acids depicted in Figure 1 result in a reaction pathway that bears similarity to mammalian urea production via the Krebs-Henseleit ornithineurea cycle. All of the ornithine-urea cycle enzymes have been isolated from several higher plants, including jack bean (18). Attempts have been made to isolate an enzyme responsible for the formation of one of the intermediates of canavanine metabolism that is distinct from its ornithine-urea cycle counterpart. These efforts have failed (3,9).One can readily demonstrate all of the ornithine-urea cycle e...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

l-Canavanine Metabolism in Jack Bean, Canavalia ensiformis (L.) DC. (Leguminosae)

Rosenthal¹

1982

Plant Physiol.

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

“…In many leguminous plants, L-canavanine, the guanidinooxy structural analog of L-arginine, serves as an important nitrogen-storing metabolite (1, 14). These plants presumably employ arginase to hydrolyze L-canavanine to L-canaline and urea (7,12).This study compared the catalytic action with regard to arginine and canavanine of the arginase from two legumes: jack bean, Canavalia ensiformis (L.) DC., a canavanine-containing plant and soybean, Glvcine max (L.) Merr. var Williams, a canavanine-free species (15).…”

mentioning

confidence: 99%

l-Arginine and l-Canavanine Metabolism in Jack Bean, Canavalia ensiformis (L.) DC. and Soybean, Glycine max (L.) Merr.

Downum¹,

Rosenthal²,

Cohen³

1983

Plant Physiol.

View full text Add to dashboard Cite

Studies have been conducted with the argnase (L-arginine amidinohydrolase, EC 3.5.3.1) of two legumes: jack bean, Canavalia enuiformis (L.) DC*, a L-canavanine-containing plant and soybean, Glycine max, a canavanine-free species. Analyses of the arginase obtained from gradientpurified mitochondria of these legumes revealed that the arginine-dependent (ADA) and canavanine-dependent activities (CDA) were localized within this orpnelle.Kinetic analyses of affinity-purified mitochondrial arginase revealed an apparent K,,, of 7 to 8 millimolar for arginine with both the jack bean and soybean arginases. Comparable determinations with canavanine revealed an apparent K,,, of 38 millimolar with the jack bean enzyme; the affinity for this arginine analog with the soybean enzyme is so poor that product formation remained linear even with a canavanine concentration of 890 millimolar.A single macromolecule appears to be responsible for both the ADA and CDA of jack bean arginase. Ion-exchange chromatography of mitochondrial arginase revealed that the ADA and CDA eluted as a single, discrete peak from DEAE-cellulose. Analyses with arginine-and canavanine-linked Sepharose failed to reveal more than one enzyme. Both the ADA and CDA increased by nearly identical amounts following elution from arginine-and canavanine-linked cyanogen bromide-activated sepharose. Neither ADA nor CDA increased preferentially over the other.Arginase (L-arginine amidinohydrolase, EC 3.5.3.1) catalyzes the hydrolysis of L-arginine to L-ornithine and urea. In many leguminous plants, L-canavanine, the guanidinooxy structural analog of L-arginine, serves as an important nitrogen-storing metabolite (1, 14). These plants presumably employ arginase to hydrolyze L-canavanine to L-canaline and urea (7,12).This study compared the catalytic action with regard to arginine and canavanine of the arginase from two legumes: jack bean, Canavalia ensiformis (L.) DC., a canavanine-containing plant and soybean, Glvcine max (L.) Merr. var Williams, a canavanine-free species (15). It sought to determine whether a single macromolecule fostered the catabolism of L-arginine and L-canavanine and to better understand the nature of these cata-'Supported by the National Science Foundation (PCM-78-20167

show abstract