Soybean leaf urease: Comparison with seed urease

Kerr, Phillip S.; Blevins, Dale G.; Rapp, Barbara J.; Randall, Douglas D.

doi:10.1111/j.1399-3054.1983.tb02297.x

Cited by 45 publications

(22 citation statements)

References 24 publications

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“…4D), observations supporting a urease role in turning over seedling nitrogen reserves. PPD is a specific (Held et al, 1976;Kobashi et al, 1985) inhibitor of plant (Kerr et al, 1983) and microbial (Martens and Bremner, 1984) ureases. The jack bean urease-PPD complex is quite stable, with a half-life of 6.4 h (McCarty et al, 1990).…”

Section: Dlscusslonmentioning

confidence: 99%

Essential Role of Urease in Germination of Nitrogen-Limited Arabidopsis thaliana Seeds

1995

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In Arabidopsis thaliana, urease transcript levels increased sharply between 2 and 4 d after germination (DAC) and were maintained at maximal levels until at least 8 DAC. Seed urease specific activity declined upon germination but began to increase in seedlings 2 DAC, reaching approximately 75% of seed activity by 8 DAC. Urea levels showed a small transient increase 1 DAC and then approximately paralleled urease activity, reaching maximal levels at approximately 9 DAC. Urease inhibition with phenylphosphorodiamidate resulted in a 2-to 4-fold increase in urea levels throughout seedling development. Arginine pools (0-8 DAC) changed approximately in parallel with the urea pool. Consistent with arginine being a major source of urea, arginase activity increased 10-fold in the interval O to 6 DAC. Allopurinol, a xanthine dehydrogenase inhibitor, had no effect on urea levels up to 3 DAC but reduced the urea pool by 30 to 40% during the interval 5 to 8 DAC, suggesting that purine degradation contributed to the urea pool well after germination, if at all. In aged Arabidopsis seeds, there was a correlation between phenylphosphorodiamidate inactivation of urease and germination inhibition, the latter overcome by NH,NO, or amino acids. Since urease activity, urea precursor, and urea increase in young seedlings, and since urease inactivation results in a nitrogen-reversible inhibition of germination, we propose that urease recycles urea-nitrogen in the seedling.

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Section: Dlscusslonmentioning

confidence: 99%

Essential Role of Urease in Germination of Nitrogen-Limited Arabidopsis thaliana Seeds

1995

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“…All urea production could be '4CO2Analysis. 14C02 was quantitated by a modification of the methods of Kerr et al (5). Freshly harvested leaf discs (0.1 g) were added to a 2.0 ml solution of 20 to 50 mM Mops (pH 6.8) containing 0.2% (v/v) Tween-20.…”

mentioning

confidence: 99%

“…were incubated with [4,5- (1), Glutamate-glyoxylate aminotransferase; (2), glycine decarboxylase; (3), serine hydroxymethyltransferase; (4), serine-glyoxylate aminotransferase; (5), D-glycerate dehydrogenase; (6), nonenzymic oxidation of glyoxylate; (7), NADPH-glyoxylate reductase; (8), glyoxylate oxidase; (9), tartronate semialdehyde synthase; (10), isomerase; (11), tartronate semialdehyde reductase. Reactions (1), (2), (3), and (4) are well documented for plants (4).…”

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Ureide Catabolism of Soybeans

Winkler¹,

Blevins²,

Polacco³

et al. 1987

Plant Physiol.

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Allantoin catabolism studies have been extended to intact leaf tissue of soybean (Glycine max L. Merr.). Phenyl (1,8,19). Despite the importance of these compounds as N metabolites, little is known about ureide catabolism. Allantoinase, the enzyme that catalyzes the hydrolysis ofallantoin to allantoate, is abundant in stems, leaves, nodules, and the fruits of soybeans (7,18,20,23). Lee and Roush (7) have reported that the soybean allantoinase is specific for DAllantoin, while others have reported that L-allantoin is catabolized, but at only 10% the rate of D-allantoin (23). N has been generally assumed to be released from allantoate through urea via urease action (9) but there is insufficient published evidence to support this hypothesis.Two allantoate catabolizing enzymes are found in microbes (22,25), allantoate amidohydrolase (ALAH)3 [EC 3.5.3.9] and '

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“…5, A and B) is less pronounced than that of leaf urease [ Fig. 4B] [7]), and in native electrophoretic mobility (Fig. 2B).…”

Section: Ure1 Activity Declines During Seedling Root Developmentmentioning

confidence: 99%

“…are distinguishable by a number of biochemical criteria, most notably Km (7,15) and pH dependence (7). Each urease isozyme is encoded by a single structural gene.…”

mentioning

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Soybean Roots Retain the Seed Urease Isozyme Synthesized during Embryo Development

Torisky¹,

Polacco²

1990

Plant Physiol.

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Roots of young soybean (Glycine max [L.] Merr.) plants (up to 25 days old) contain two distinct urease isozymes, which are separable by hydroxyapatite chromatography. These two urease species (URE1 and URE2) differ in: (a) electrophoretic mobility in native gels, (b) pH dependence, and (c) recognition by a monoclonal antibody specific for the seed ("embryo-specific") urease. By these parameters root URE1 urease is similar to the abundant embryo-specific urease isozyme, while root URE2 resembles the "ubiquitous" urease which has previously been found in all soybean tissues examined (leaf, embryo, seed coat, and cultured cells). The embryo-specific and ubiquitous urease isozymes are products of the Eul and Eu4 structural genes, respectively. Roots of the eul-sun/eul-sun genotype, which lacks the embryo-specific urease (i.e. 'seed urease-null'), contain no URE1 urease activity. Roots of eu4/eu4, which lacks ubiquitous urease, lack the URE2 (leaflike) urease activity. From these genetic and biochemical criteria, then, we conclude that UREl and URE2 are the embryo-specific and ubiquitous ureases, respectively. Adventitious roots generated from cuttings of any urease genotype lack URE1 activity. In seedling roots the seedlike (URE1) activity declines during development. Roots of 3-week-old plants contain 5% of the total UREI activity of the radicle of 4-day-old seedlings, which, in turn, has approximately the same urease activity level as the dormant embryonic axis. The embryo-specific urease incorporates label from [35S]methionine during embryo development but not during germination, indicating that there is no de novo synthesis of the embryo-specific (URE1) urease in the germinating root. We conclude that the seedlike urease (URE1) found in roots of young soybean plants is a remnant of the Eul-encoded, abundant, embryo-specific urease which accumulates in the embryonic root axis during seed development.

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Soybean leaf urease: Comparison with seed urease

Cited by 45 publications

References 24 publications

Essential Role of Urease in Germination of Nitrogen-Limited Arabidopsis thaliana Seeds

Essential Role of Urease in Germination of Nitrogen-Limited Arabidopsis thaliana Seeds

Ureide Catabolism of Soybeans

Soybean Roots Retain the Seed Urease Isozyme Synthesized during Embryo Development

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