关键区别 - NADH vs fadh2
Acoenzymeis an organic non-protein molecule which is relatively small in size and has the ability to carry chemical groups betweenenzymes并充当电子载体。NADH(烟酰胺腺嘌呤二核苷酸)和FADH2(黄素腺嘌呤二核苷酸)是几乎所有生化途径中使用的两个主要辅酶。他们充当电子载体并参与oxidation-reductionreactions of reaction intermediates.NADH是维生素B3的衍生物(烟酸/烟酰胺) while FADH2 is a derivative of Vitamin B2 (Riboflavin).This is the key difference between NADH and FADH2.
内容
1.Overview and Key Difference
2.What is NADH
3.What is FADH2
4.Similarities Between NADH and FADH2
5.Side by Side Comparison – NADH vs FADH2 in Tabular Form
6。概括
What is NADH?
NADH is synthesized from Vitamin B3 (Niacin) and is a coenzyme composed of ribosylnicotinamide 5′-diphosphate coupled to adenosine 5′-phosphate. It serves as an electron carrier in many reactions by alternatively converting to its oxidized (NAD+) form and the reduced (NADH) form. The reduced NADH acts as an electron donor and oxidize to NAD+while reducing the other compound involved in the reaction. This role of NADH is involved in the processes of糖酵解,TCA周期and in the electron transport chain where NADH is one of the electron donors.

Figure 01: Structures of NADH and NAD+
NADH的熔点为140.0 - 142.0°C,可以在体内合成,不是必需的营养素。但是,必需维生素烟酸的缺乏会导致体内NADH组成的减少。纳德在cytosolas well as in the线粒体. The mitochondrial membrane is impermeable to NADH, and this barrier distinguishes between cytoplasmic and mitochondrial NADH stores.
在商业应用中,NADH管理orally in order to combat fatigue as well as during energy deprived syndromes and metabolic disorders
What is FADH2?
FADH2 is synthesized from the water-soluble vitamin B2, which is also known as Riboflavin. FADH2 is the reduced form of flavin adenine dinucleotide (FAD).
FAD is synthesized from riboflavin and two molecules ofATP. Riboflavin is phosphorylated by ATP to produce riboflavin 5′-phosphate (also called flavin mononucleotide, FMN). FAD is then formed from FMN by the transfer of an AMP molecule fromATP.

Figure 02: Structures of FAD and FADH
Fadh参与了两种碳水化合物代谢and fatty acid metabolism. In carbohydrate metabolism, FADH is involved in harvesting high energy electron rich fuels in the TCA cycle. FADH is generated in each round of fatty acid oxidation, and the fatty acyl chain is shortened by two carbon atoms as a result of these reactions to yield Acetyl Co A. FADH acts as an electron donor in the electron transport.
What are the Similarities Between NADH and FADH2?
- NADH and FADH2 are coenzymes
- 两者都充当电子载体。
- Both are nonprotein organic molecules.
- Both are derived from vitamins.
- Both are water soluble.
- Both can exist in the reduced form or oxidized form.
- Both participate in oxidation and reduction reactions and help in the transfer of electrons from one substrate to the other.
- Both coenzymes can be synthesized in the body.
- 这两个分子都参与包括碳水化合物的代谢途径,脂肪酸,氨基酸和核苷酸代谢。
NADH和FADH2有什么区别?
NADH vs FADH2 |
|
NADH is a coenzyme derived from vitamin B3 or niacin. | FADH2 is a coenzyme derived from Vitamin B2 or riboflavin. |
ATP Produced | |
NADH gives 3 ATP. | NADH给出了2个ATP。 |
Commercial Applications | |
NADH is used as a supplement under energy deprived conditions. | This has no commercial applications. |
概括– NADH vs FADH2
NADH和FADH2的作用是将电子捐赠给电子传输链并充当电子载体,该电子载体将电子从不同的代谢途径释放到最终能源生产过程,即电子传输链。他们都通过向氧分子提供氢分子来捐赠电子,以在电子传输链中产生水。因此,NADH和FADH2在所有代谢过程中都是至关重要的。NADH和FADH2之间的差异是NADH是源自维生素B3或烟酸的辅酶,而FADH2是衍生自维生素B2或核黄素的辅酶。
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参考:
1. “FADH2.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine,Available here. Accessed 4 Sept. 2017.
2.“Introduction to NAD/NADH.” Introduction to NAD/NADH,Available here. Accessed 4 Sept. 2017.
3. “NADH.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine,Available here. Accessed 4 Sept. 2017.
Image Courtesy:
1.“图07 01 01AB”CNX OpenStax(CC BY 4.0)viaCommons Wikimedia
2. “FADH2 production by flavin reductase for HOCl generation and halogenase activity” By Jmont31 – Diagram made with ChemDraw(CC BY-SA 4.0)viaCommons Wikimedia
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