Open AccessPhotosynthesis in the Higher Plant Vicia faba
Author(s) -
Samuel S. Kent
Publication year - 1979
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.64.1.159
Subject(s) - citric acid cycle , vicia faba , citrate synthase , biochemistry , photosynthesis , crassulacean acid metabolism , biology , photorespiration , vicia , autotroph , amino acid , aconitase , malate dehydrogenase , tricarboxylic acid , formate , mitochondrion , metabolism , botany , enzyme , bacteria , genetics , catalysis
In the higher plant Vicia faba, anomalous labeling patterns in the organic acids and related amino acids of the tricarboxylic acid cycle which result from photosynthetic (14)CO(2) fixation (in conjunction with an enzyme localization pattern unique to plant mitochondria) suggest that the tricarboxylic acid cycle functions primarily as a pathway leading to glutamic acid biosynthesis during autotrophic growth. The distribution of isotope in citrate indicates little recycling of oxaloacetate for the resynthesis of citrate. Rather, malate appears to provide both the C(2) and C(4) fragments for the synthesis of citrate, and [(3)H]formate and (14)CO(2)-labeling patterns implicate serine as the ultimate C(3) precursor of malate.