Last Updated on July 28, 2021 by QCity Editorial Stuff
NADH and NADPH are two types of nad that are used in the electron transport chain. These nads differ by one phosphate group, so they have different chemical formulas: NADH has three phosphates while NADPH has four. This difference between NADH vs. NADPH is essential because this phosphate group allows for a higher level of reduction to occur on the way back up through the electron transport chain.
Nadh VS Nadph
NADH has three phosphates, while NADPH has four. This difference between NADH vs. NADPH is essential because this phosphate group allows for a higher level of reduction to occur on the way back up through the electron transport chain.
This means that NADPH can be used as an oxidizing agent, making it more reactive than NADH (which cannot serve in this capacity). The most common oxidation reactions involving NADPH are fatty acid synthesis and lactic acid fermentation. In both cases, electrons from two glucose molecules or one molecule of glycerol enter into the ATP synthase complex, with one being converted into CO₂, whereas the other becomes H₉O.
NADPH can be used as an oxidizing agent, making it more reactive than NADH (which cannot serve in this capacity). The most common oxidation reactions involving NADPH are fatty acid synthesis and lactic acid fermentation. In both cases, electrons from two glucose molecules or one molecule of glycerol enter into the ATP synthase complex, with one being converted into CO₂, whereas the other becomes H₉O.
It is essential to balance NADH vs. NADPH because too much NADPH will cause oxidative stress, while too many nadph cells would result in wasted energy due to lack of reactivity.
NADH vs. nadph on cellular metabolism is also evident in NADH-dependent nitric oxide synthase, which is involved in the synthesis of NO. In this process, nadh converts arginine into citrulline and then to urea through a series of reactions with NADPH as an intermediate.
NADH levels are generally higher than those found for NADPH because it can be produced from oxidative phosphorylation or by breaking down nadh in glycolysis. Likewise, nadph can be generated by the pentose phosphate pathway or through NADH oxidation to NADP+.
The high reactivity of these two types of compounds is essential when considering their role in creating ATP and other cellular metabolism reactions. The more reactive form will always take precedence over less reactive forms so that electrons do not become trapped on a single molecule without moving onto another one.
Many nad-dependent enzymes exist, but nadh vs. nadph is most notable because it dictates how effectively the electron chain can function due to its different abilities as an oxidizing agent. It also provides insight into metabolic pathways that rely on NADPH or nadh to convert molecules back into H₉O or CO₂ during oxidative phosphorylation, where it takes place at Complexes I and II, respectively.
NADH is a more stable molecule than NADP+, so this difference in reactivity between these two types helps regulate critical reactions within cells. This stabilization has lessened over time with evolution such that there is now no need for NADPH since all cellular processes have become nadph dependent.
The nadh vs. nadph distinction provides insight into how metabolic pathways work and why it’s essential to maintain the balance of both molecules, but what do they do when their levels are out of whack? When nadh becomes too high, oxidative stress will occur as opposed to increased energy production like it would be if nadp were prevalent instead. Likewise, an excess amount of nadph leads to decreased nadh levels, and this will cause a reduction in the amount of ATP generated.
What Is Nadh?
NADH stands for nicotinamide adenine dinucleotide, a molecule with two molecules of niacin (vitamin B) and one molecule of adenosine. NADH can be found in every cell because it helps convert glucose to carbon dioxide by producing ATP through the process known as oxidative phosphorylation. Due to its ability to produce ATP, nadh is also essential when muscles require energy, such as during exercise or periods where they are not being used but may need to be increased due to fever or sickness. This conversion occurs at Complexes I and II, respectively, with nadph playing a more active role than nadh does at these sites. In addition to being more reactive than nadh, nadph is also found in higher levels.
What Is Nadph?
NADPH stands for nicotinamide adenine dinucleotide phosphate because its structure includes a second molecule of niacin and one molecule of phosphoric acid. NADPH can be used to reduce oxidized glutathione back into reduced form, or it may create ATP through the process known as fermentation when glucose or glycerol are broken down by yeast cells. In this case, electrons from these molecules enter Complex I, where they become H₉O instead of CO₂, like during glucose conversion with nadh at Complexes I and II, respectively. The pentose phosphate pathway provides another way nadph can be produced. This pathway includes nadh for other metabolic pathways like glycolysis and gluconeogenesis that need NADPH as a critical component.
Can Nadh VS. Nadph Have An Out-Of-Balance Relationship?
When nadh becomes too high, oxidative stress will occur instead of increased energy production if nadp was prevalent. Likewise, when nadp levels are higher than they should be to nadh, this leads to decreased ATP generation because there is not enough naidh available for the electron chain process, which occurs at Complexes I and II, respectively, depending on where it needs more enzyme activity.”
For example, during conditions such as fever or illness that lead to increased nadp levels, nadh decreases, and ATP production reduces as a result.
What Does Nadph Produce?
NADPH produces ATP through the process of fermentation when glycerol or glucose are broken down by yeast cells. This type of production is used as a last resort because it creates less than one-third the amount that oxidative phosphorylation generates (in this process, electrons from molecules like those mentioned go into Complex I, where they become H₉O instead).
When nadph doesn’t have enough NADH available, then the pentose phosphate pathway provides another way nadph can be produced. “This pathway is needed for other metabolic pathways like glycolysis and gluconeogenesis that need nadh as a critical component.”