Anapleurotic CO/sub 2/ fixation by phosphoenolpyruvate carboxylase in C/sub 3/ plants. [Nicotiana tabacum]
The role of phosphoenolpyruvate carboxylase in photosynthesis in the C/sub 3/ plant Nicotiana tabacum has been probed by measurement of the /sup 13/C content of various materials. Whole leaf and purified ribulose bisphosphate carboxylase are within the range expected for C/sub 3/ plants. Aspartic acid purified following acid hydrolysis of this ribulose bisphosphate carboxylase is enriched in /sup 13/C compared to whole protein. Carbons 1-3 of this aspratic acid are in the normal C/sub 3/ range, but carbon-4 (obtained by treatment of the aspartic acid with aspartate ..beta..-decarboxylase) has an isotopic composition in the range expected for products of C/sub 4/ photosynthesis (-5%), and it appears that more than half of the aspartic acid is synthesized by phosphoenolpyruvate carboxylase using atmospheric CO/sub 2//HCO/sub 3//sup -/. Thus, a primary role of phosphoenolpyruvate carboxylase in C/sub 3/ plants appears to be the anapleurotic synthesis of four-carbon acids.
- Research Organization:
- Univ. of Wisconsin, Madison
- DOE Contract Number:
- AC02-83ER13076; FG02-86ER13534
- OSTI ID:
- 5900461
- Journal Information:
- Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 84:1; ISSN PLPHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ASPARTIC ACID
BIOSYNTHESIS
CARBON 13
CARBON DIOXIDE FIXATION
CARBON ISOTOPES
CARBON-CARBON LYASES
CARBOXY-LYASES
CARBOXYLASE
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
ENZYME ACTIVITY
ENZYMES
EVEN-ODD NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
LYASES
METABOLISM
NICOTIANA
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHYSIOLOGY
PLANTS
STABLE ISOTOPES
SYNTHESIS
TRACER TECHNIQUES