The fate of carbon during the assimilation of carbamoyl phosphate in white spruce seedlings as revealed by [14C]-carbamoyl phosphate, [14C]-cyanate, and [14C] -bicarbonate labeling patterns |
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Authors: | D J Durzan |
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Institution: | Dept. of Pomology, Univ. of California, Davis, CA, 95616, USA |
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Abstract: | The fate of carbamoyl phosphate in white spruce seedlings revolves around the production of spontaneous degradation products, cyanate, bicarbonate, and carba-mate. When 14C]-carbamoyl phosphate and 14C]-cyanate are assimilated, urea is a common early metabolic intermediate that appears in the alcohol soluble N. By contrast, urea is not detected among the products of 14C]-bicarbonate. Carbamoyl phosphate and glutamic acid are implicated as having pivotal roles in the production of amides, arginine, and biotin. Within 2-h exposures to radioactive substrates considerably more carbon from bicarbonate was diverted into amino acids Incorporated into proteins than with carbon-nitrogen substrates. Specific activities of bound amino acid residues support the view that proteins formed from these 14C]-substrates have different rates of metabolic turnover. |
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Keywords: | Carbon-14 fertilizers nitrogen Picea glauca |
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