The key difference between ATP and NADPH is that the ATP is the energy currency of many of the living organisms while the NADPH is the typical coenzyme used for the reduction reactions of anabolic processes seen in plants.
Adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH) are phosphorylated compounds present in organisms. ATP is the energy transfer currency in most organisms. When there is an energy requirement, ATP readily provides the energy for the process. On the other hand, NADPH works as an electron carrier in plants during the photosynthesis. Hence NADPH is an important reducing molecule in major food production process of plants.
CONTENTS
1. Overview and Key Difference
2. What is ATP
3. What is NADPH
4. Similarities Between ATP and NADPH
5. Side by Side Comparison – ATP vs NADPH in Tabular Form
6. Summary
What is ATP?
Adenosine triphosphate (ATP) is the energy currency in living cells. It is a nucleotide with three major components namely, a ribose sugar, triphosphate group and an adenine base. ATP molecules bear high energy within the molecules. Therefore, upon an energy request for growth and metabolism, ATP hydrolyses and releases its energy for cellular needs. Three phosphate groups of the ATP molecule are alpha (α), beta (β), and gamma (γ) phosphates. The activity of ATP mainly depends on the triphosphate group because the energy of ATP comes from the two high-energy phosphate bonds (phosphoanhydride bonds) formed between phosphate groups. The Gamma phosphate group is the first phosphate group hydrolyzed upon an energy requirement, and it locates farthest from the ribose sugar.
Figure 01: ATP
ATP is an unstable molecule. Hence, the hydrolysis of ATP is always feasible via an exergonic reaction. When the terminal phosphate group removes from the ATP molecule, and it converts into Adenosindiphoshate (ADP). This conversion releases 30.6 kJ/mol of energy to cells. ADP converts back into ATP immediately inside the mitochondria by the enzyme called ATP synthase during the cellular respiration. Cells produce ATP via several processes such as substrate-level phosphorylation, oxidative phosphorylation, and photophosphorylation.
Other than working as an energy currency, ATP fulfils several other functions as well. It acts as a coenzyme in glycolysis. It can be found in nucleic acids during the processes of DNA replication and transcription. Furthermore, it has the ability to chelate metals.
What is NADPH?
NADPH is a typical coenzyme that works as an electron carrier in many processes of plants. It is also called as reducing the power of the biochemical reactions. NADPH is present at higher concentrations in the cells. It provides electrons and become oxidized, and the oxidized form of NADPH is NADP+. NADPH acts as a coenzyme of various dehydrogenase enzymes.
Figure 02: NADPH
Furthermore, NADPH is able to undergo reversible oxidation-reduction reactions. The oxidation of NADPH is thermodynamically favourable. Hence it is an exergonic reaction. In anabolic reactions such as such as lipid and nucleic acid synthesis, NADPH serves as a reducing agent. In photosynthesis, NADPH acts as a reducing agent in the Calvin cycle to assimilate CO2. Chemical formula and the molecular mass of the NADPH are C21H29N7O17P3 and 744.42 g·mol−1 respectively.
What are the Similarities Between ATP and NADPH?
- They are phosphorylated compounds.
- Both require for anabolic as well as catabolic reactions.
- They contain energy.
- Both are nucleotides.
- Both contain three phosphate groups.
- Ribose ring is present in both molecules.
- During the photosynthesis, ATP and NADPH are utilized and synthesized.
What is the Difference Between ATP and NADPH?
ATP is a versatile energy currency for cells while NADPH is a source of electrons that can pass along to an electron acceptor. The function of ATP is that it acts as a major energy storing and transferring molecule. On the other hand, NADPH works as a coenzyme and reducing the power of biochemical reactions.
The below infographic presents the difference between ATP and NADPH in tabular form.
Summary – ATP vs NADPH
Adenosine triphosphate (ATP) is an important nucleotide found in cells. It is known as the energy currency of life, and its value is only second to DNA of the cell. It is a high energy molecule that has the chemical formula of C10H16N5O13P3. ATP is mainly consists ADP and a phosphate group. There are three major components in an ATP molecule namely a ribose sugar, an adenine base and a triphosphate group. NADPH serves as an electron carrier in a number of reactions. It can be oxidized (NADP+) and reduced (NADPH). It also works as a coenzyme of various dehydrogenase enzymes. This is the difference between ATP and NADPH.
Reference:
1.Editors. “NADPH – Definition and Function.” Biology Dictionary, Biology Dictionary, 29 Apr. 2017. Available here
2.“ATP Molecule.” The ATP Molecule -Chemical and Physical Properties. Available here
Image Courtesy:
1.”Figure 07 01 02″By CNX OpenStax (CC BY 4.0) via Commons Wikimedia
2.”NADPH Structure”By Macyliz – Own work, (CC BY-SA 3.0) via Commons Wikimedia