What is the Difference Between DHAP and G3P

The key difference between DHAP and G3P is that dihydroxyacetone phosphate (DHAP) is a three-carbon sugar involved in triglycerides synthesis, while glyceraldehydes 3 phosphate (G3P) is a three-carbon sugar that is an intermediate of the glycolytic pathway.

Monosaccharides are sugars that contain about 3 to 8 carbons atoms. They are simple sugars that cannot be hydrolyzed into smaller sugars and have the general formula of C_nH_2nO_n. Based on their functional group, they are two types as aldoses (having aldehydic group) and ketoses (having ketonic group). Furthermore, based on the number of carbon atoms, they are further classified as trioses (3 carbon atoms), tetroses (4 carbon atoms), pentoses (5 carbon atoms) and hexoses (6 carbon atoms). DHAP and G3P are sugars that have three carbon atoms.

CONTENTS

1. Overview and Key Difference
2. What is DHAP
3. What is G3P
4. Similarities – DHAP and G3P
5. DHAP vs G3P in Tabular Form
6. Summary – DHAP vs G3P

What is DHAP?

Dihydroxyacetone phosphate (DHAP) is a three-carbon sugar that is a precursor for triglycerides synthesis. It is also called glycerine phosphate in older texts. DHAP is the phosphate ester of dihydroxyacetone. It also has an anionic form with the chemical formula HOCH₂C(O)CH₂OPO₃²-. This anion is involved in many metabolic pathways, including the Calvin cycle in plants and glycolysis reaction. In the Calvin cycle, DHAP is one of the products of sixfold reduction of 1-3 bisphosphoglycerate through NADPH. DHAP is usually used for the production of sedoheptulose1, 7 bisphosphate and fructose 1,6 bisphosphate. Both these molecules are used to reform ribulose 5 phosphate, which is the key carbohydrate molecule of the Calvin cycle.

In glycolysis, it is one of the two products resulting from the breakdown of fructose 1,6 bisphosphate along with glyceraldehyde 3 phosphate. It rapidly converts to glyceraldehydes 3 phosphate by the action of the triosephosphate isomerase enzyme. Glyceraldehyde 3 phosphate is a very important intermediate in glycolysis that makes cellular ATP. Furthermore, the conversion of DHAP to L-glycerol 3 phosphate provides adipose cells with the precursor (activated glycerol backbone) they require to synthesize new triglycerides. DHAP also has a role in the lipid biosynthesis process in the protozoan parasite; Leishmania mexicana. Furthermore, DHAP is a precursor for 2-oxopropanol (pyruvaldehyde), which is a flavouring agent.

What is G3P?

Glyceraldehydes 3 phosphate (G3P) is a three-carbon sugar that is an intermediate of the glycolysis pathway. It is a monophosphate ester of glyceraldehydes. It also has an anion state with the chemical formula of H(O)CCH(OH)CH₂OPO₃^2-.  G3P is an intermediate metabolite that occurs in several central metabolic pathways of all organisms. It is an intermediate in both glycolysis and gluconeogenesis.

G3P is also an important intermediate in photosynthesis. Furthermore, G3P occurs as a by-product in the biosynthesis of tryptophan. Tryptophan is an essential amino acid that cannot be produced by the human body. Moreover, glyceraldehydes 3 phosphate is an important reactant molecule in the biosynthesis of thiamine (vitamin B1). Thiamine is another substance that cannot be produced by the human body.

What are the Similarities Between DHAP and G3P?

• DHAP and G3P are three-carbon sugars.
• They are monosaccharides.
• These molecules are isomers.
• They have the same molecular formula.
• Both are produced by the breaking down of fructose 1,6 bisphosphate.
• These molecules are involved in metabolic pathways.
• Both molecules can be in the anionic state.
• They have a phosphate group in the structure.

What is the Difference Between DHAP and G3P?

DHAP is a three-carbon sugar involved in triglycerides synthesis while G3P is a three-carbon sugar that is an intermediate of the glycolysis pathway. So, this is the key difference between DHAP and G3P. Furthermore, DHAP has a ketonic group as the functional group, while G3P has an aldehydic group as the functional group.

The below infographic presents the differences between DHAP and G3P in tabular form for side by side comparison.

Summary – DHAP vs G3P

DHAP and G3P are sugars that have three carbon atoms. Since their molecular formula is the same, they are isomers of each other.  DHAP is a three-carbon monosaccharide involved in triglycerides synthesis while G3P is a three-carbon monosaccharide that is an intermediate of the glycolysis pathway. Thus, this is the difference between DHAP and G3P.

Reference:

1. “Dihydroxyacetone Phosphate.” American Chemical Society.
2. “Glycolysis Enzymes – Biochemistry.” Private Tutoring.

Image Courtesy:

1. “Dihydroxyacetone phosphate to glycerol 3-phosphate en” By Xvazquez – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Oxydation G3P”  By Pancrat – Own work (CC BY-SA 3.0) via Commons Wikimedia