Glyceraldehyde

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Glyceraldehyde
Glyceraldehyde v2.svg
D-Glyceraldehyde 2D Fischer.svg
Names
IUPAC name
Glyceraldehyde
Systematic IUPAC name
2,3-Dihydroxypropanal
Other names
Glyceraldehyde
Glyceric aldehyde
Glyceral
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.000.264 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C3H6O3/c4-1-3(6)2-5/h1,3,5-6H,2H2 Yes check.svgY
    Key: MNQZXJOMYWMBOU-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C3H6O3/c4-1-3(6)2-5/h1,3,5-6H,2H2
    Key: MNQZXJOMYWMBOU-UHFFFAOYAU
  • O=CC(O)CO
  • OCC(O)C=O
Properties [1]
C3H6O3
Molar mass 90.078 g·mol−1
Density 1.455 g/cm3
Melting point 145 °C (293 °F; 418 K)
Boiling point 140 to 150 °C (284 to 302 °F; 413 to 423 K) at 0.8 mmHg
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Glyceraldehyde (glyceral) is a triose monosaccharide with chemical formula C 3 H 6 O 3. It is the simplest of all common aldoses. It is a sweet, colorless, crystalline solid that is an intermediate compound in carbohydrate metabolism. The word comes from combining glycerol and aldehyde, as glyceraldehyde is glycerol with one alcohol group oxidized to an aldehyde.

Contents

Structure

Glyceraldehyde has one chiral center and therefore exists as two different enantiomers with opposite optical rotation:

D-glyceraldehyde
(R)-glyceraldehyde
(+)-glyceraldehyde		L-glyceraldehyde
(S)-glyceraldehyde
(−)-glyceraldehyde
Fischer projection D-Glyceraldehyde 2D Fischer.svg L-Glyceraldehyde 2D Fischer.svg
Skeletal formula D-glyceraldehyde-2D-skeletal.svg L-glyceraldehyde-2D-skeletal.svg
Ball-and-stick model D-glyceraldehyde-3D-balls.png L-glyceraldehyde-3D-balls.png

While the optical rotation of glyceraldehyde is (+) for R and (−) for S, this is not true for all monosaccharides. The stereochemical configuration can only be determined from the chemical structure, whereas the optical rotation can only be determined empirically (by experiment).

It was by a lucky guess that the molecular D- geometry was assigned to (+)-glyceraldehyde in the late 19th century, as confirmed by X-ray crystallography in 1951. [2]

Nomenclature

In the D/L system, glyceraldehyde is used as the configurational standard for carbohydrates. [3] Monosaccharides with an absolute configuration identical to (R)-glyceraldehyde at the last stereocentre, for example C5 in glucose, are assigned the stereo-descriptor D-. Those similar to (S)-glyceraldehyde are assigned an L-.

Chemical synthesis

Glyceraldehyde can be prepared, along with dihydroxyacetone, by the mild oxidation of glycerol, for example with hydrogen peroxide [4] and a ferrous salt as catalyst.[ citation needed ]

Its cyclohexylidene acetal can also be produced by oxidative cleavage of the bis(acetal) of mannitol. [5]

Biochemistry

The enzyme glycerol dehydrogenase (NADP+) has two substrates, glycerol and NADP+, and 3 products, D-glyceraldehyde, NADPH and H+. [6]

The interconversion of the phosphates of glyceraldehyde (glyceraldehyde 3-phosphate) and dihydroxyacetone (dihydroxyacetone phosphate), catalyzed by the enzyme triosephosphate isomerase, is an intermediate step in glycolysis.

See also

Related Research Articles

A dehydrogenase is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN. Like all catalysts, they catalyze reverse as well as forward reactions, and in some cases this has physiological significance: for example, alcohol dehydrogenase catalyzes the oxidation of ethanol to acetaldehyde in animals, but in yeast it catalyzes the production of ethanol from acetaldehyde.

Carbohydrate metabolism is the whole of the biochemical processes responsible for the metabolic formation, breakdown, and interconversion of carbohydrates in living organisms.

A tetrose is a monosaccharide with 4 carbon atoms. They have either an aldehyde functional group in position 1 (aldotetroses) or a ketone functional group in position 2 (ketotetroses).

Fatty acid metabolism consists of various metabolic processes involving or closely related to fatty acids, a family of molecules classified within the lipid macronutrient category. These processes can mainly be divided into (1) catabolic processes that generate energy and (2) anabolic processes where they serve as building blocks for other compounds.

<span class="mw-page-title-main">Glyceraldehyde 3-phosphate</span> Chemical compound

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. With the chemical formula H(O)CCH(OH)CH2OPO32-, this anion is a monophosphate ester of glyceraldehyde.

Dihydroxyacetone phosphate (DHAP, also glycerone phosphate in older texts) is the anion with the formula HOCH2C(O)CH2OPO32-. This anion is involved in many metabolic pathways, including the Calvin cycle in plants and glycolysis. It is the phosphate ester of dihydroxyacetone.

<span class="mw-page-title-main">1,3-Bisphosphoglyceric acid</span> Chemical compound

1,3-Bisphosphoglyceric acid (1,3-Bisphosphoglycerate or 1,3BPG) is a 3-carbon organic molecule present in most, if not all, living organisms. It primarily exists as a metabolic intermediate in both glycolysis during respiration and the Calvin cycle during photosynthesis. 1,3BPG is a transitional stage between glycerate 3-phosphate and glyceraldehyde 3-phosphate during the fixation/reduction of CO2. 1,3BPG is also a precursor to 2,3-bisphosphoglycerate which in turn is a reaction intermediate in the glycolytic pathway.

Glyceraldehyde-3-phosphate dehydrogenase (NADP+) (GAPN) is an enzyme that irreversibly catalyzes the oxidation of glyceraldehyde-3-phosphate (GAP) to 3-phosphoglycerate using the reduction of NADP+ to NADPH. GAPN is used in a variant of glycolysis that conserves energy as NADPH rather than as ATP. The NADPH and 3-PG can then be used for synthesis. The most familiar variant of glycolysis uses glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoglycerate kinase to produce ATP. GAPDH is phosphorylating. GAPN is non-phosphorylating.

<span class="mw-page-title-main">Aldose reductase</span> Enzyme

In enzymology, aldose reductase is a cytosolic NADPH-dependent oxidoreductase that catalyzes the reduction of a variety of aldehydes and carbonyls, including monosaccharides. It is primarily known for catalyzing the reduction of glucose to sorbitol, the first step in polyol pathway of glucose metabolism.

sn-Glycerol 3-phosphate is the organic ion with the formula HOCH2CH(OH)CH2OPO32-. It is one of two stereoisomers of the ester of dibasic phosphoric acid (HOPO32-) and glycerol. It is a component of glycerophospholipids. From a historical reason, it is also known as L-glycerol 3-phosphate, D-glycerol 1-phosphate, L-α-glycerophosphoric acid.

<span class="mw-page-title-main">Glycerol-3-phosphate dehydrogenase</span> Class of enzymes

Glycerol-3-phosphate dehydrogenase (GPDH) is an enzyme that catalyzes the reversible redox conversion of dihydroxyacetone phosphate to sn-glycerol 3-phosphate.

<span class="mw-page-title-main">Glycerol dehydrogenase</span>

Glycerol dehydrogenase (EC 1.1.1.6, also known as NAD+-linked glycerol dehydrogenase, glycerol: NAD+ 2-oxidoreductase, GDH, GlDH, GlyDH) is an enzyme in the oxidoreductase family that utilizes the NAD+ to catalyze the oxidation of glycerol to form glycerone (dihydroxyacetone).

In enzymology, a glycerol-3-phosphate 1-dehydrogenase (NADP+) (EC 1.1.1.177) is an enzyme that catalyzes the chemical reaction

Glycerol-3-phosphate dehydrogenase (NAD<sup>+</sup>)

In enzymology, a glycerol-3-phosphate dehydrogenase (NAD+) (EC 1.1.1.8) is an enzyme that catalyzes the chemical reaction

In enzymology, a glycerol dehydrogenase (NADP+) (EC 1.1.1.72) is an enzyme that catalyzes the chemical reaction

<span class="mw-page-title-main">Phosphogluconate dehydrogenase (decarboxylating)</span>

In enzymology, a phosphogluconate dehydrogenase (decarboxylating) (EC 1.1.1.44) is an enzyme that catalyzes the chemical reaction

In enzymology, a glyceraldehyde-3-phosphate dehydrogenase (NAD(P)+) (EC 1.2.1.59) is an enzyme that catalyzes the chemical reaction

In enzymology, a glyceraldehyde-3-phosphate dehydrogenase (NADP+) (phosphorylating) (EC 1.2.1.13) is an enzyme that catalyzes the chemical reaction

The enzyme methylglyoxal synthase catalyzes the chemical reaction

Fructolysis refers to the metabolism of fructose from dietary sources. Though the metabolism of glucose through glycolysis uses many of the same enzymes and intermediate structures as those in fructolysis, the two sugars have very different metabolic fates in human metabolism. Unlike glucose, which is directly metabolized widely in the body, fructose is almost entirely metabolized in the liver in humans, where it is directed toward replenishment of liver glycogen and triglyceride synthesis. Under one percent of ingested fructose is directly converted to plasma triglyceride. 29% - 54% of fructose is converted in liver to glucose, and about a quarter of fructose is converted to lactate. 15% - 18% is converted to glycogen. Glucose and lactate are then used normally as energy to fuel cells all over the body.

References

  1. ↑ Merck Index, 11th Edition, 4376
  2. ↑ Determination of the Absolute Configuration of Optically Active Compounds by Means of X-Rays Nature 168, 271-272 J. M. BIJVOET, A. F. PEERDEMAN & A. J. van BOMMEL doi : 10.1038/168271a0
  3. ↑ "22.03: The D and L Notation". Chemistry LibreTexts. 2015-03-19. Retrieved 2022-01-09.
  4. ↑ Wu, Gongde; Wang, Xiaoli; Jiang, Taineng; Lin, Qibo (2015-11-27). "Selective Oxidation of Glycerol with 3% H2O2 Catalyzed by LDH-Hosted Cr(III) Complex". Catalysts. 5 (4): 2039–2051. doi: 10.3390/catal5042039 . ISSN   2073-4344.
  5. ↑ Dhatrak, N. R.; Jagtap, T. N.; Shinde, A. B. (2022). "Preparation of 1,2:5,6-Di-O-cyclohexylidene-D-mannitol and 2,3-Cyclohexylidene-D-glyceraldehyde". Organic Syntheses. 99: 363–380. doi: 10.15227/orgsyn.099.0363 . S2CID   254320929.
  6. ↑ Kormann, Alfred W.; Hurst, Robert O.; Flynn, T.G. (1972). "Purification and properties of an NADP+-dependent glycerol dehydrogenase from rabbit skeletal muscle". Biochimica et Biophysica Acta (BBA) - Enzymology. 258 (1): 40–55. doi:10.1016/0005-2744(72)90965-5. PMID   4400494.
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