ASN Amino Acid
Asparagine is a type of an alpha-amino acid which is amongst the 20 amino acids which are found in the animal proteins. It is useful in the protein biosynthesis. It consists of an alpha-amino group, an alpha carboxylic group, and a carboxamide, which is a side chain and distributes it in the form of polar aliphatic amino acids. The reaction between the asparagine and the reducing sugars or any other sources of the carbonyls tends to produce acrylamide in the food when it is heated to a sufficient required temperature. These products are found in the baked food items such as potato chips, french fries and toasted bread.
The aliphatic amino acids are nonpolar and hydrophobic. Some of the examples include alanine, leucine, valine, isoleucine, and proline. The structure of the aliphatic compounds is either unsaturated and having double bonds, or saturated and having single bonds. They can even have triple bonds. There are many different kinds of elements which bond to the carbon chain including oxygen, nitrogen, sulphur and chlorine. They are generally flammable and often used in the form of liquefied natural gas and the form of hydrocarbons as a fuel.
Today we will discuss the ASN amino acid, asparagine role, asparagine structure, the physical and chemical properties of asparagine, and its sources and deficiency in detail.
Asparagine Structure
The chemical structure of the asparagine amino acid is given below.
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The asparagine amino acid consists of an alpha-amino group, an alpha carboxylic group, and a side chain of carboxamide. All these classify asparagine functional groups as a polar aliphatic amino acid. However, asparagine is a non-essential amino acid in the human body since our body can synthesize it on its own.
Physical and Chemical Properties of Asparagine Functional Group
Let us now discuss the physical and chemical properties of asparagine which are noted as follows.
The chemical formula of the asparagine amino acid is C4H8N203.
It has a molecular mass of 132.19g/mol.
Under the standard conditions, it appears as a white crystal.
The density of asparagine is 1.543 g/cm3.
The melting point of asparagine is 507K and the boiling point is 711K.
Asparagine is partially soluble in water and has a 2.94g/100mL solubility.
The compound of asparagine has a structure which is an orthorhombic crystal.
Asparagine Role
Let us now take a look at some of the functions of asparagine which are given as follows.
The residues of the asparagine compound are found usually in the beta-sheets at the top of alpha-helices in the form of ASX motifs and the ASX turns, which are similar to the turn motifs.
It helps in maintaining the equilibrium which is needed for the central nervous system in humans.
It also helps to control the metabolic activities of the brain.
Asparagine is also responsible for the proper functioning of the cells in our body and nervous system. It helps in preventing our brain from being extremely nervous or calm.
The asparagine amino acids are known as non-essential amino acids and are produced by our liver.
It also plays a crucial role in the synthesis of a huge number of proteins.
Sources of Asparagine
Asparagine is readily available in many food items. However, it is not crucial for us humans since they are incorporated from the transnational metabolic pathway. Some of the food sources of asparagine are as follows.
Asparagine is found in a large amount in the form of plant proteins.
The plant sources of asparagine include soy, whole grains, legumes, nuts, lactalbumin, whey, eggs, poultry, fish, beef, and dairy products.
It is also found in french fries and toasted bread.
Asparagine Deficiency
The deficiency of asparagine in the human body tends to show the following symptoms.
Headaches
Irritability
Confusion
Depression
Psychosis
FAQs on Asparagine Amino Acid
1. What is Asparagine and what are its main functions in the body?
Asparagine (Asn) is a non-essential amino acid, meaning the human body can produce it on its own. Its primary function is as a building block for proteins. It also plays a vital role in the metabolic control of cell functions in nerve and brain tissue and is essential for the synthesis of glycoproteins. Asparagine is crucial for maintaining equilibrium in the central nervous system.
2. What is the chemical structure of the asparagine amino acid?
The chemical structure of asparagine consists of a central alpha-carbon atom bonded to four different groups: an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom (-H), and a distinctive side chain. The side chain for asparagine is -CH₂CONH₂, which contains a carboxamide group.
3. Why is asparagine classified as a polar, neutral amino acid?
Asparagine is classified as:
- Polar: Because its side chain contains a carboxamide group (-CONH₂), which has polar C=O and N-H bonds. This allows it to form hydrogen bonds with water and other polar molecules.
- Neutral: Because the side chain has no overall electrical charge at physiological pH (around 7.4). Unlike acidic or basic amino acids, it does not donate or accept a proton under normal biological conditions.
4. What is the key difference between Asparagine (Asn) and Aspartic Acid (Asp)?
The key difference lies in their side chains. Asparagine has a carboxamide group (-CONH₂), which is neutral. In contrast, Aspartic Acid has a carboxylic acid group (-COOH). This functional group difference means Asparagine is a neutral amino acid, while Aspartic Acid is an acidic amino acid because its side chain can deprotonate to -COO⁻.
5. What are the one-letter and three-letter codes for asparagine?
In biochemistry, standard abbreviations are used to represent amino acids in protein sequences. For asparagine, the codes are:
- Three-letter code: Asn
- One-letter code: N
6. Is asparagine an essential or non-essential amino acid for humans?
Asparagine is a non-essential amino acid. This means the human body can synthesise it from other precursors, primarily from another amino acid, aspartic acid, through the action of the enzyme asparagine synthetase. Therefore, it is not required to be obtained directly from the diet.
7. What is the role of asparagine in forming peptide bonds and protein structures?
Like all amino acids, asparagine's alpha-amino group and alpha-carboxyl group participate in forming peptide bonds to create the primary structure (the polypeptide chain) of proteins. Furthermore, its polar side chain can form hydrogen bonds, which are crucial for stabilising the secondary (alpha-helices, beta-sheets) and tertiary structures of proteins, thereby defining their final three-dimensional shape and function.
8. What are some common food sources of asparagine?
Asparagine is found in a wide variety of foods. Some of the most common dietary sources include:
- Vegetables: Asparagus (from which it was first isolated and named), potatoes, and legumes.
- Animal Products: Dairy products, beef, poultry, eggs, and fish.
- Other sources: Nuts, seeds, and whole grains.
9. How does asparagine's side chain participate in N-linked glycosylation?
The side chain of asparagine plays a unique and critical role in a process called N-linked glycosylation. The nitrogen atom of its amide group (-CONH₂) acts as an attachment point for complex carbohydrate chains (glycans). This post-translational modification is vital for the proper folding, stability, targeting, and function of many proteins that are destined for secretion or insertion into cell membranes.
10. How does asparagine exist as a zwitterion at physiological pH?
At a neutral physiological pH of approximately 7.4, asparagine exists as a zwitterion. In this form, its acidic carboxyl group (-COOH) loses a proton to become a negatively charged carboxylate ion (-COO⁻), while its basic amino group (-NH₂) gains a proton to become a positively charged ammonium ion (-NH₃⁺). The molecule has both a positive and a negative charge, but its overall net charge is zero.
