What is the Difference Between ATP and NADPH

The main difference between ATP and NADPH is that the hydrolysis of ATP releases energy whereas the oxidation of NADPH provides electrons. Furthermore, ATP serves as the main energy currency of the cell while NADPH serves as a coenzyme with the reducing power needed by the biochemical reactions.

ATP and NADPH are two types of adenosine nucleotides important in the metabolic reactions. Both ATP and NADPH contain phosphate groups.

Key Areas Covered

1. What is ATP
     – Definition, Structure, Role in the Cell
2. What is NADPH
     – Definition, Structure, Role in the Cell
3. What are the Similarities Between ATP and NADPH
     – Outline of Common Features
4. What is the Difference Between ATP and NADPH
     – Comparison of Key Differences

Key Terms

ATP, Coenzyme, Electrons, Energy Currency, NADPH, Reducing Agent

What is ATP

ATP (Adenosine triphosphate) is the main energy currency of the cell. The synthesis of new biomolecules, cell division, and movement use the energy produced by the hydrolysis of ATP. Furthermore, this converts ATP either into A. On the other hand, cellular respiration is the process responsible for the production of ATP. The organelle responsible for cellular respiration in animals is the mitochondrion. Both bacteria and yeast produce ATP via fermentation. For instance, photophosphorylation is the process which produces ATP in plants during photosynthesis.

Figure 1: ATP Structure

Furthermore, ATP molecule consists of an adenosine group and three phosphate groups attached to a ribose sugar. Each phosphate group is attached to the core molecule through an oxygen atom. The first phosphate group attached to the ribose sugar is the alpha-phosphate group while the second or the beta-phosphate group is attached to the alpha-phosphate group via a phosphoanhydride bond. The third phosphate group, on the other hand, is the gamma-phosphate group attached to the beta-phosphate group via the same type of bond. The two phosphoanhydride bonds between phosphate groups are the high energy bonds that can be hydrolyzed to obtain energy.

What is NADPH

NADPH is the reduced form of NADP (nicotinamide adenine dinucleotide phosphate), which serves as a coenzyme in the redox reaction of photosynthesis. Since NADPH provides both electrons and protons to the chemical reaction, it is a strong reducing agent. The light reaction of photosynthesis produces NADPH and the dark reaction uses this coenzyme. In animals, the pentose phosphate pathway is responsible for the production of NADPH.

Figure 2: NADPH Function

NADPH differs from NADH by the presence of a phosphate group on the 2’ position of the ribose sugar. This phosphate group links the adenine moiety to the core molecule.

Similarities Between ATP and NADPH

• ATP and NADPH are two types of adenine nucleotides that link biochemical reactions.
• The ribose sugar makes the core of the both.
• Also, both molecules contain an adenine group.
• Additionally, both are phosphorylated.
• Moreover, both of them play a role in photosynthesis.

Difference Between ATP and NADPH

Definition

ATP refers to a phosphorylated nucleotide, composed of adenosine and three phosphate groups while supplying energy for many biochemical, cellular processes by undergoing enzymatic hydrolysis, especially to ADP. In contrast, NADPH refers to a cofactor that is used to donate electrons and hydrogens to reactions catalyzed by some enzymes. Thus, these definitions contain the main difference between ATP and NADPH.

Chemical Formula

The chemical formula of ATP is C₁₀H₁₆N₅O₁₃P₃ while the chemical formula of NADPH is C₂₁H₂₉N₇O₁₇P₃.

Role

Another difference between ATP and NADPH is that ATP is the energy currency of the cell while NAPDH is the main reducing power of the cell.

Synthesis

The pathway of synthesis contibutes to another difference between ATP and NADPH. Cellular respiration, photophosphorylation, and fermentation are the pathways that produce ATP while pentose phosphate pathway in animals and light reaction of photosynthesis in plants are the pathways that produce NADPH.

Usage

ATP provides energy to various types of biochemical reactions including anabolic reactions, cell division, and movement while NADPH provides electrons and protons to the dark reaction of photosynthesis and many biosynthetic and redox reactions in animals. Therefore, this is another difference between ATP and NADPH.

Conclusion

ATP is the main energy currency of the cell. Its hydrolysis release energy needed by most of the biochemical reactions inside the cell. On the other hand, NADPH is the main reducing power of the cell. It provides both electrons and hydrogen atoms to biochemical reactions. Most importantly, NADPH is a cofactor. Thus, the main difference between ATP and NADPH is their role inside the cell.

References:

1. Bonora, Massimo et al. “ATP synthesis and storage” Purinergic signalling vol. 8,3 (2012): 343-57. Available Here
2. Matsushima, Shouji et al. “Physiological and pathological functions of NADPH oxidases during myocardial ischemia-reperfusion” Trends in cardiovascular medicine vol. 24,5 (2014): 202-5. Available Here

Image Courtesy:

1. “Figure 06 04 01” By CNX OpenStax –  (CC BY 4.0) via Commons Wikimedia  
2. “Figure 1. Overall reaction for the formation of superoxide from NADPH” By Marckhalaf – Own work (CC BY-SA 3.0) via Commons Wikimedia