Aspartate
n., plural: aspartates
[əsˈpɑː(ɹ)teɪt]
Definition: a salt of aspartic acid
Table of Contents
What Is Aspartate?
Aspartate is an amino acid involved in protein production. Like all other amino acids, it possesses both carboxylic acid and an amino group. In normal physiological conditions, the -NH+ is protonated as an amino group while COO is deprotonated as a carboxylic acid group. The ionic form of aspartic acid is known as aspartate. It is symbolized as symbol Asp.
There is an acidic side chain (CH2COOH) in the Aspartic acid that reacts in the body with other amino acids, proteins, and enzymes. Under physiological parameters (pH 7.4), the side chain in proteins is normally the negatively charged aspartate form, COO.
The human body can synthesize it according to the requirement. The GAU and GAC are two codons that encode it.
Aspartate sidechains in proteins are frequently bonded by hydrogen to create asx motifs or asx turns, which are found at the N-termini of alpha helices.
The L-isomer of aspartate is one of the 22 proteinogenic amino acids or protein building blocks. Like glutamic acid, it has a pKa of 3.9, making it an acidic amino acid; but, in a peptide, its pKa can be as high as 14 according to the circumstances. Aspartate is an important biosynthetic building block.
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Aspartate (also known as aspartic acid) is a nonessential amino acid that is used in the biosynthesis of proteins. It is classified as an acidic amino acid due to the presence of a carboxyl group (-COOH) on its side chain. Aspartate is one of the 20 amino acids that are used to build proteins in living organisms and is found in high concentrations in many protein-rich foods such as meat, fish, and dairy products.
Discovery of Aspartate
In 1827, Étienne Ossian Henry and Auguste-Arthur Plisson discovered aspartic acid by hydrolyzing asparagine, which was extracted from asparagus juice in 1806. This process allowed them to determine the molecular pharmacology of aspartic acid by breaking the asparagine. Lead hydroxide was used in their initial method, but since then, a wide variety of other acids and bases have become significantly more common.
Forms and Nomenclature
Aspartic acid is available in two forms or enantiomers. The term “aspartic acid” can apply to either an enantiomer or a combination of the two. Only one of these two types, “L-aspartic acid” is directly absorbed into proteins. Its homolog, D-aspartic acid, has relatively little biological relevance. In contrast to enzymatic synthesis, most chemical synthesis produces both forms of “DL-aspartic acid,” also recognized as a racemic mixture.
Synthesis
Let’s find out how aspartate is produced biologically and chemically.
Biosynthesis
The transamination of oxaloacetate is the metabolic pathway that most frequently results in aspartate synthesis in the human body. Alpha-keto acid and Aspartate are the products that result from the action of an amino-transferase enzyme during the production of aspartate. Here, an amine group from one particle (such as alanine or glutamine) is moved to another.
Chemical synthesis
Industrial production of aspartate involves the process of fumarate amination, which is facilitated by L aspartate ammonia-lyase.
(C6H4(CO)2NC(CO2Et)2)-Diethyl sodium phthalimide malonate can be used to make racemic aspartic acid.
Metabolism
Aspartate is the constituent of various other amino acids in plants and microorganisms, including four important for humans: threonine, methionine, lysine, and isoleucine. Aspartate is converted to these other amino acids by first reducing it to its “semialdehyde,”. Transamination is used to create asparagine from aspartate.
-O2CCH(NH2)CH2CO2– + GC(O)NH3+ O2CCH(NH2)CH2CONH3+ + GC(O)O
(where GC(O)NH2 and GC(O)OH are glutamine and glutamic acid,respectively)
Being charged and polar molecules, aspartates like to be exposed to an aqueous environment on the surface of proteins. When buried inside the protein, Aspartates (and Glutamates) are typically implicated in salt bridges, in which they pair with a positively charged amino acid (such as Arginine) to form hydrogen bonds that might be essential for protein stability.
Aspartates are typically found in the active or binding regions of proteins. They can bind with non-protein atoms having positively charged (cations) such as zinc, due to their negative charge. (Russelllab, 2023)
Allosteric inhibition molecules like cytidine triphosphate (CTP) are a perfect illustration of feedback inhibition, which occurs when the final product of a biosynthetic pathway prevents an enzyme from initiating a reaction at the beginning of the procedure. (Lennarz & Lane, 2013)
Other Biochemical Roles
The amino acid aspartate is involved in a wide variety of different biochemical processes. It is a metabolite that is formed during the process known as the urea cycle, but it is also involved in the process known as gluconeogenesis. This is accomplished by a process referred to as the malate-aspartate shuttle, which takes advantage of a streamlined reaction mechanism between aspartate and oxaloacetate, an oxidized (dehydrogenated) derivative of malic acid. The shuttle tends to make use of the simple interconversion between these two compounds. This mechanism transports reducing equivalents.
Aspartate is responsible for the contribution of one nitrogen atom in the process of biosynthesis which results in the formation of inosine that acts as a precursor to purine bases. Within an ATP synthase chain, aspartic acid acts in the capacity of a hydrogen acceptor. It has been discovered that the L-aspartic acid found in food can cause inhibition of the enzyme beta-glucuronidase, which is responsible for regulating the circulation of bilirubin and bile acids through the enterohepatic circulation.
An amino group is transferred from aspartate to glutamate via the enzyme aspartate transaminase in a reversible manner. This is crucial for the metabolism of amino acids, hence the presence of this enzyme is essential.
The following organs and tissues contain AST: the liver, the heart, the red blood cells, the kidneys, the brain, and the gall bladder.
Serum AST, ALT (alanine transaminase), and their ratio (AST/ALT ratio) are commonly tested because they are considered to be clinical biomarkers for the health of the liver.
Interactive pathway map
Glycolysis is the process by which glucose is converted into pyruvate and hydrogen ions during metabolism. During this process, free energy is generated, which is then put to use in the production of ATP and NADH.
Gluconeogenesis is a metabolic pathway that makes glucose from carbon substrates that are not carbohydrates. These carbon substrates include pyruvate, glycerol, lactate, glucogenic amino acids, and fatty acids. Gluconeogenesis occurs in all living organisms.
Following is the interactive pathway map of humans.
Figure 4: Interactive pathway map. Image Credit: Wikipathways.org
Neurotransmitter
The conjugate base of aspartic acid is aspartate which activates NMDA receptors, however not as strong as the amino acid neurotransmitter L-glutamate.
Applications & Market
Aspartic acid had a global market volume of 39.3 thousand short tonnes in 2014, which corresponds to approximately $117 million per year; however, there are potential growth areas that account for a configurable market volume of $8.78 billion (Bn). The United States of America, Western Europe, and China are the top three market segments, respectively. Some of the applications that are currently in use include biodegradable polymers (poly aspartic acid), sweets with fewer calories, resins, and corrosion inhibitors.
Superabsorbent polymers
It is expected that the demand for (SAP) biodegradable superabsorbent polymers and hydrogels will increase due to the use of aspartic acid. Disposable diapers account for approximately 75% of the usage of superabsorbent polymers, while the rest is utilized in feminine sanitation and geriatric incontinence products. Poly-aspartic acid, a by-product of aspartic acid polymerization, can substitute polyacrylate. Polyacrylate is not biodegradable. Just about one percent of SAP’s global market is comprised of the poly-aspartate segment.
Additional uses
Aspartic acid has diverse applications beyond its use in SAP. For instance, it is utilized in the fertilizer industry, which is valued at $19 billion. The poly aspartate pathway enhances water retention and nitrogen uptake. Aspartic acid also has applications in the solid concrete floor coatings industry, which is worth $1.1 billion as of 2020. Polyaspartic serves as a low-VOC and low-energy substitute for conventional epoxy resins. Additionally, it is utilized in the scale and corrosion inhibitors market, which is worth over $5 billion.
Dietary Sources
Aspartic acid is necessary but a non-essential amino acid means that it can be made by the body from intermediates in the central metabolic pathway and does not need to be consumed through food. Aspartic acid makes up about one of every 20 amino acids that eukaryotic cells add to a protein. Because of this, almost all protein sources that are good for you contain aspartic acid.
In addition, aspartic acid is present in:
1. Aspartic acid or its salts are found in dietary supplements (such as magnesium aspartate)
2. Aspartic acid and phenylalanine make up the artificial sweetener aspartame.
Health Benefits
Below are some of the health benefits of aspartate.
- Potassium aspartate supplements are required for maintaining the body’s fluid homeostasis. It also prevents dehydration by regulating sodium levels in the body.
- L Aspartate is a secure and efficient therapy for hepatic encephalopathy in patients with cirrhosis.
- Aspartate is typically mixed with other minerals to boost the body’s absorption of those minerals and to improve athletic performance.
- In addition, the creation of energy in the body is contributed by aspartic acid. It also assists in the transmission of chemical impulses throughout the nervous system.
Side Effects
Even though it may be unusual, some individuals may experience extremely harmful side effects. If you notice any of the following symptoms or signs that could suggest a serious adverse impact, you should contact your doctor or seek emergency medical attention: (Drugs.com., 2023)
- Symptoms of an allergic reaction, such as hives, rash, swollen red blisters, itching, fever, skin peeling, tightness of the throat, difficulty in breathing, wheezing chest, difficulty in swallowing, or speaking, unusual hoarseness or swelling of the face, throat, tongue or lips.
- Gastrointestinal distress or vomiting up stomach contents.
- Extreme cases of diarrhea
Fold Change and Aspartate
Fold change refers to the difference in expression levels of a gene or protein between two conditions or treatments. In the case of aspartate, fold change may refer to the difference in its concentration or expression levels between two experimental conditions, such as before and after a treatment, or between two groups of samples.
For example, if the concentration of aspartate in a group of samples is found to be 2 times higher after treatment compared to before treatment, the fold change would be 2. Fold change is commonly used in gene and protein expression studies to quantify changes in expression levels and to identify potential biomarkers or targets for further investigation.
Can aspartate be used as a treatment for neurodegenerative diseases?
There is growing evidence that aspartate may have the potential as a treatment for neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Aspartate plays a key role in the function of the brain and nervous system and has been shown to have neuroprotective properties. However, more research is needed to determine the optimal dose and treatment protocol and to better understand the mechanisms underlying aspartate’s neuroprotective effects.
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References
- Drugs.com. (2023). Magnesium aspartate Side Effects. Retrieved 04 March, 2023, from https://www.drugs.com/sfx/magnesium-aspartatework%20properly.
- Aspartates. (2022). Retrieved 04 March, 2023, from https://www.rxlist.com/aspartates/supplements.htm
- Lennarz, W. J., & Lane, M. D. (2013). Encyclopedia of biological chemistry: Academic Press.
- Rochester, U. o. R. M. C. (2023). Aspartic Acid. Retrieved 04 March, 2023, from https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=19&contentid=AsparticAcid#:~:text=It%20helps%20make%20other%20amino,signals%20through%20the%20nervous%20system.
Russelllab. (2023). Aspartate. Retrieved 04 March, 2023, from http://www.russelllab.org/aas/Asp.html - Sidhu, S. S. (2018). l-Ornithine l-Aspartate is Effective and Safe for the Treatment of Hepatic Encephalopathy in Cirrhosis. Journal of clinical and experimental hepatology, 8(3), 219-221.
- WikiPathWays. (2021). Glycolysis and gluconeogenesis (WP534). Retrieved 04 March, 2023, from https://www.wikipathways.org/pathways/WP534.html
- Gangloff, J., Keith, G., Ebel, J.P. and Dirheimer, G., 1971. Structure of aspartate-tRNA from brewer’s yeast. Springer Nature New Biology, 230(12), pp.125-126.
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