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Ureide catabolism of soybeans

Journal Article · · Plant Physiol.; (United States)
OSTI ID:6438419

Allantoin catabolism studies have been extended to intact leaf tissue of soybean (Glycine max L. Merr.) Phenyl phosphordiamidate, one of the most potent urease inhibitors known does not inhibit /sup 14/CO/sub 2/ release from (2,7-/sup 14/C)allantoin (urea labeled), but inhibits urea dependent CO/sub 2/release greater than or equal to99.9% under similar conditions. Furthermore, /sup 14/CO/sub 2/ and /sup 14/C) allantoate are the only detectable products of (2,7-/sup 14/C)allantoin catabolism. Neither urea nor any other product were detected by analysis on HPLC organic acid or organic base columns although urea and all commercially available metabolites that have been implicated in allantoin and glyoxylate metabolism can be resolved by a combination of these two columns. In contrast, when allantoin was labeled in the two central, nonureido carbons ((4,5-/sup 14/C)allantoin), its catabolism to (/sup 14/)allantoate, /sup 14/CO/sub 2/,(/sup 14/C)glyoxylate, (/sup 14/C)glycine, and (/sup 14/C)serine in leaf discs could be detected. These data are fully consistent with the metabolism of allantoate by two amidohydrolase reactions (neither of which is urease) that occur at similar rates to release glyoxylate, which in turn is metabolized via the photorespiratory pathway. This is the first evidence that allantoate is metabolized without urease action to NH/sub 4//sup +/ and CO/sub 2/ and that carbons 4 and 5 enter the photorespiratory pathway.

Research Organization:
Univ. of Missouri, Columbia
OSTI ID:
6438419
Journal Information:
Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 83:3; ISSN PLPHA
Country of Publication:
United States
Language:
English