3-Phosphoglyceric acid (3PG, 3-PGA, or PGA) is the conjugate acid of 3-phosphoglycerateorglycerate 3-phosphate (GPorG3P).[1] The glycerate is a biochemically significant metabolic intermediate in both glycolysis and the Calvin-Benson cycle. This anion is often termed as PGA when referring to the Calvin-Benson cycle. In the Calvin-Benson cycle, 3-phosphoglycerate is typically the product of the spontaneous scission of an unstable 6-carbon intermediate formed upon CO2 fixation. Thus, two equivalents of 3-phosphoglycerate are produced for each molecule of CO2 that is fixed.[2][3][4] In glycolysis, 3-phosphoglycerate is an intermediate following the dephosphorylation (reduction) of 1,3-bisphosphoglycerate.[4]: 14
In the glycolytic pathway, 1,3-bisphosphoglycerate is dephosphorylated to form 3-phosphoglyceric acid in a coupled reaction producing two ATP via substrate-level phosphorylation.[5] The single phosphate group left on the 3-PGA molecule then moves from an end carbon to a central carbon, producing 2-phosphoglycerate.[5][a] This phosphate group relocation is catalyzed by phosphoglycerate mutase, an enzyme that also catalyzes the reverse reaction.[6]
^Rose, Z.B.; Dube, S. (1976). "Rates of phosphorylation and dephosphorylation of phosphoglycerate mutase and bisphosphoglycerate synthase". Journal of Biological Chemistry. 251 (16): 4817–4822. doi:10.1016/S0021-9258(17)33188-5. PMID8447.
^Andersson, I. (2008). "Catalysis and regulation in Rubisco". Journal of Experimental Botany. 59 (7): 1555–1568. doi:10.1093/jxb/ern091. PMID18417482.
^ abPettersson, G.; Ryde-Pettersson, Ulf (1988). "A mathematical model of the Calvin photosynthesis cycle". European Journal of Biochemistry. 175 (3): 661–672. doi:10.1111/j.1432-1033.1988.tb14242.x. PMID3137030.
^Fridlyand, L.E.; Scheibe, R. (1999). "Regulation of the Calvin cycle for CO2 fixation as an example for general control mechanisms in metabolic cycles". Biosystems. 51 (2): 79–93. doi:10.1016/S0303-2647(99)00017-9. PMID10482420.
^Igamberdiev, A.U.; Kleczkowski, L.A. (2018). "The Glycerate and Phosphorylated Pathways of Serine Synthesis in Plants: The Branches of Plant Glycolysis Linking Carbon and Nitrogen Metabolism". Frontiers in Plant Science. 9 (318). doi:10.3389/fpls.2018.00318. PMID29593770.{{cite journal}}: CS1 maint: unflagged free DOI (link)
^Hanford, J.; Davies, D.D. (1958). "Formation of Phosphoserine from 3-Phosphoglycerate in Higher Plants". Nature. 182: 532–533. doi:10.1038/182532a0.
^Cowgill, R.W.; Pizer, L.I. (1956). "PURIFICATION AND SOME PROPERTIES OF PHOSPHORYLGLYCERIC ACID MUTASE FROM RABBIT SKELETAL MUSCLE". Journal of Biological Chemistry. 223 (2): 885–895. doi:10.1016/S0021-9258(18)65087-2. PMID13385236.
^Hofer, H.W. (1974). "Separation of glycolytic metabolites by column chromatography". Analytical Biochemistry. 61 (1): 54–61. doi:10.1016/0003-2697(74)90332-7. PMID4278264.
^Shibayama, J.; Yuzyuk, T.N.; Cox, J.; et al. (2015). "Metabolic Remodeling in Moderate Synchronous versus Dyssynchronous Pacing-Induced Heart Failure: Integrated Metabolomics and Proteomics Study". PLoS One. doi:10.1371/journal.pone.0118974. PMID25790351.{{cite journal}}: CS1 maint: unflagged free DOI (link)
^Xu, J.; Zhai, Y.; Feng, L. (2019). "An optimized analytical method for cellular targeted quantification of primary metabolites in tricarboxylic acid cycle and glycolysis using gas chromatography-tandem mass spectrometry and its application in three kinds of hepatic cell lines". Journal of Pharmaceutical and Biomedical Analysis. 171: 171–179. doi:10.1016/j.jpba.2019.04.022.
^Note that 3-phosphoglycerate and 2-phosphoglycerate are isomers of one another