Chemistry:Glyceraldehyde 3-phosphate

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Glyceraldehyde 3-phosphate
D-Glycerinaldehyde 3-phosphate deprotonated V1.svg
Names
IUPAC name
2-hydroxy-3-oxopropyl dihydrogen phosphate
Identifiers
3D model (JSmol)
1725008
ChEBI
ChEMBL
ChemSpider
DrugBank
EC Number
  • 209-721-7
KEGG
MeSH Glyceraldehyde+3-Phosphate
UNII
Properties
C3H7O6P
Molar mass 170.058
Melting point 102–104 °C[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Glyceraldehyde 3-phosphate, also known as triose phosphate or 3-phosphoglyceraldehyde and abbreviated as G3P, GA3P, GADP, GAP, TP, GALP or PGAL, is a metabolite that occurs as an intermediate in several central pathways of all organisms.[2][3] With the chemical formula H(O)CCH(OH)CH2OPO32-, this anion is a monophosphate ester of glyceraldehyde.

An intermediate in both glycolysis and gluconeogenesis

Formation

D-glyceraldehyde 3-phosphate is formed from the following three compounds in reversible reactions:

  • Fructose-1,6-bisphosphate (F1,6BP), catalyzed by aldolase.
β-D-fructose 1,6-bisphosphate fructose-bisphosphate aldolase D-glyceraldehyde 3-phosphate dihydroxyacetone phosphate
Beta-D-fructose-1,6-bisphosphate wpmp.png D-glyceraldehyde-3-phosphate wpmp.png + Glycerone-phosphate wpmp.png
Biochem reaction arrow reversible NNNN horiz med.svg
fructose-bisphosphate aldolase

Compound C05378 at KEGG Pathway Database. Enzyme 4.1.2.13 at KEGG Pathway Database. Compound C00111 at KEGG Pathway Database. Compound C00118 at KEGG Pathway Database.

The numbering of the carbon atoms indicates the fate of the carbons according to their position in fructose 6-phosphate.

  • Dihydroxyacetone phosphate (DHAP), catalyzed by triose phosphate isomerase.
Dihydroxyacetone phosphate triose phosphate isomerase D-glyceraldehyde 3-phosphate
Glycerone-phosphate wpmp.png   D-glyceraldehyde-3-phosphate wpmp.png
Biochem reaction arrow reversible NNNN horiz med.svg
 
  triose phosphate isomerase

Compound C00111 at KEGG Pathway Database.Enzyme 5.3.1.1 at KEGG Pathway Database.Compound C00118 at KEGG Pathway Database.

As a substrate

  • To produce 1,3-bisphospho-D-glycerate in glycolysis.
glyceraldehyde 3-phosphate glyceraldehyde phosphate dehydrogenase D-glycerate 1,3-bisphosphate
D-glyceraldehyde-3-phosphate wpmp.png   1,3-bisphospho-D-glycerate.svg
NAD+ + Pi NADH + H+
Biochem reaction arrow reversible YYYY horiz med.svg
NAD+ + Pi NADH + H+
 
 

Compound C00118 at KEGG Pathway Database. Enzyme 1.2.1.12 at KEGG Pathway Database. Reaction R01063 at KEGG Pathway Database. Compound C00236 at KEGG Pathway Database.

D-glyceraldehyde 3-phosphate is also of some importance since this is how glycerol (as DHAP) enters the glycolytic and gluconeogenic pathways. Furthermore, it is a participant in and a product of the pentose phosphate pathway.

Interactive pathway map

An intermediate in photosynthesis

During plant photosynthesis, 2 equivalents of glycerate 3-phosphate (GP; also known as 3-phosphoglycerate) are produced by the first step of the light-independent reactions when ribulose 1,5-bisphosphate (RuBP) and carbon dioxide are catalysed by the rubisco enzyme. The GP is converted to D-glyceraldehyde 3-phosphate (G3P) using the energy in ATP and the reducing power of NADPH as part of the Calvin cycle. This returns ADP, phosphate ions Pi, and NADP+ to the light-dependent reactions of photosynthesis for their continued function. RuBP is regenerated for the Calvin cycle to continue.

G3P is generally considered the prime end-product of photosynthesis and it can be used as an immediate food nutrient, combined and rearranged to form monosaccharide sugars, such as glucose, which can be transported to other cells, or packaged for storage as insoluble polysaccharides such as starch.

Balance sheet

6 CO2 + 6 RuBP (+ energy from 12 ATP and 12 NADPH) →12 G3P (3-carbon)

10 G3P (+ energy from 6 ATP) → 6 RuBP (i.e. starting material regenerated)

2 G3Pglucose (6-carbon).

In tryptophan biosynthesis

Glyceraldehyde 3-phosphate occurs as a byproduct in the biosynthesis pathway of tryptophan, an essential amino acid that cannot be produced by the human body.

In thiamine biosynthesis

Glyceraldehyde 3-phosphate occurs as a reactant in the biosynthesis pathway of thiamine (Vitamin B1), another substance that cannot be produced by the human body.

References

  1. "metabocard for Glycerol 3-phosphate". http://www.hmdb.ca/metabolites/HMDB0000126. 
  2. Berg, Jeremy M.; Tymoczko, Stryer (2002). Biochemistry (5th ed.). New York: W.H. Freeman and Company. ISBN 0-7167-3051-0. https://archive.org/details/biochemistrychap00jere. 
  3. Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN:1-57259-153-6.

External links