Introduction to Valine
Valine is an amino acid formed by the hydrolysis of proteins. German chemist Emil Fischer did the first isolation of Valine in 1901 from compound casein. It is an essential amino acid for mammals and fowls as they cannot synthesise and may require dietary sources. It is synthesised by microorganisms and plants from pyruvic acid, a by-product of the breakdown of carbohydrates. The molecular formula is C5H11NO2.
Valine is a branched-chain amino acid and is used in the body to help make energy. Valine is mainly found in protein food sources such as soy, meats, fish, and dairy and vegetables, whole grains, and nuts.
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What are the Uses of the Valine?
The amino acid valine holds a few uses-
Valine acid is used in food additives as flavouring agents, human drugs for pediatric investigation plans, and cosmetics for antistatic and hair conditioning.
It is used in supplement, biochemical and nutritional investigations, and cultural media.
It is also commonly used in anti encephalopathic, flavours or additives, and essential amino acids.
D-Valine holds an extensive industrial application. It is used as an intermediate for synthesising veterinary antibiotics, agricultural pesticides, and drugs.
What is Glycine Valine?
Glycine or glycine valine is the simplest amino acid that is obtained by the hydrolysis of proteins. It is a sweet-tasting compound and is the earliest valine acid to be isolated from gelatin. It is highly rich in silk fibroin and gelatin.
Glycine is the most nonessential amino acid for mammals as they synthesise this compound from the amino acids- threonine and serine and do not require dietary sources. The molecular formula of glycine is C7H14N2O3 and is also known as Glycyl-DL-valine and Glycylvaline2325.
What is Leucine Valine?
Leucine valine is an amino acid that is found naturally in the human body. Leucine is a non-polar and aliphatic hydrocarbon that comprises four-carbon side chains from the simple amino acid structure. The molecular formula of leucine valine is C6H13NO2 and is commonly known as L-leucine and (S)-2-Amino-4-methylpentanoic acid.
Leucine is a white crystal with a density of 1.293 g/cu cm at 18 °C.
Leucine is highly essential for protein synthesis and is vital for several metabolic functions. It contributes to the growth and repair of bone tissues and muscles, regulation of blood-sugar levels, increases growth hormone production, and promotes wound healing.
Similarities Between Valine and Leucine
Valine and leucine are standard amino acids that are grouped as branched-chain amino acids or BCAAs. These amino acids are essential to human life. They are highly required for the physiological response to stress and energy production, particularly for the normal metabolism and health of muscle.
Valine and leucine are branched-chain amino acids that help in the building of physical strength. The BCAAs can help in the reduction of muscle loss and fosters a faster muscle recovery.
Role of Leucine in the body
Leucine is highly significant for the general health of muscle and helps in stimulating protein synthesis and reducing protein breakdown, especially of muscle protein following physical trauma.
Like Valine, leucine is also known to increase the insulin levels in the blood, leading to a similar effect on the proteins in muscle tissue. Another significant importance of leucine is in regulating blood sugar levels as it is a source of gluconeogenesis, which is the synthesis of glucose from non-carbohydrates on the liver. The process of gluconeogenesis helps the body and the muscles to heal.
Similarities Between Valine and Isoleucine
Valine and isoleucine fall under the branched-chain amino acids (BCAAs) and comprise about 17 percent of human skeletal muscle. Valine and isoleucine are essential amino acids that need to be provided by dietary protein and are transported via circulation to skeletal muscle. These amino acids are used to support protein synthesis.
The BCAA valine and leucine also act as signalling molecules to activate the muscle protein synthetic machinery. They help in stimulating muscle protein synthesis and help to promote muscle growth. BCCAs also play a significant role in the development of insulin resistance.
What is Serine?
Serine and Valine are similar amino acids present in the human body. Serine is a nonessential amino acid synthesised by the human body and is present in several proteins. Serine with an alcohol group is required to metabolise fatty acids, cell membranes, fats, a healthy immune system, and muscle growth.
The molecular formula of serine is C3H7NO3. It plays a vital role in purine, pyrimidine, porphine, and creatine biosynthetic pathways.
Even though serine and Valine are present in the same amount in the human body, serine is mainly found in the active site of the serine protease enzyme, which includes two major components- chymotrypsin and trypsin.
FAQs on Valine
1. What is Valine and what is its chemical formula?
Valine is an α-amino acid that is essential for human health. It is one of the 20 common amino acids that make up proteins in the body. Its chemical formula is C₅H₁₁NO₂. Structurally, it features a central carbon atom bonded to an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom, and a distinctive isopropyl side chain (-CH(CH₃)₂).
2. Why is Valine classified as an essential amino acid?
Valine is classified as an essential amino acid because the human body cannot produce it on its own in sufficient quantities. Therefore, it must be obtained through dietary sources. Its synthesis pathway is absent in humans, making its consumption crucial for protein synthesis, tissue repair, and various metabolic functions.
3. How does the structure of Valine make it a neutral and nonpolar amino acid?
Valine is considered a neutral amino acid because it contains one acidic carboxyl group (-COOH) and one basic amino group (-NH₂), which neutralize each other. It is classified as nonpolar (or hydrophobic) because its side chain is an isopropyl group, which is an alkyl group composed of only carbon and hydrogen. This nonpolar side chain repels water and influences the three-dimensional folding of proteins.
4. What are the primary functions of Valine in the body?
Valine plays several important roles in the body. Its primary functions include:
- Stimulating muscle growth and tissue regeneration.
- Serving as a source of energy for muscles during physical activity.
- Maintaining mental vigour and emotional calm.
- Supporting the proper functioning of the nervous system.
- Maintaining nitrogen balance in the body.
5. In what form does Valine exist in aqueous solution near neutral pH?
In an aqueous solution near neutral pH (approximately 7.4), Valine exists as a Zwitterion. This is a dipolar ion where the acidic carboxyl group (-COOH) donates a proton and becomes a negatively charged carboxylate ion (-COO⁻), while the basic amino group (-NH₂) accepts a proton to become a positively charged ammonium ion (-NH₃⁺). Although it has both positive and negative charges, the overall charge of the molecule is zero.
6. What are some common dietary sources of Valine?
Since Valine is an essential amino acid, it must be consumed through food. High-protein foods are typically rich in Valine. Common sources include:
- Dairy products: Cheese, milk, and yogurt.
- Meat and Poultry: Beef, chicken, and pork.
- Fish: Tuna, salmon, and cod.
- Legumes: Soybeans, lentils, and beans.
- Nuts and Seeds: Peanuts, almonds, and sesame seeds.
- Whole Grains: Oats and brown rice.
7. What is the significance of Valine being a Branched-Chain Amino Acid (BCAA)?
The significance of Valine being a Branched-Chain Amino Acid (BCAA), along with leucine and isoleucine, lies in its unique metabolic pathway. Unlike most other amino acids, which are metabolised in the liver, BCAAs are primarily broken down in the muscles. This makes them a readily available source of energy during exercise, helps reduce muscle fatigue, and plays a direct role in stimulating muscle protein synthesis, making them popular among athletes.
8. What genetic codons specify the amino acid Valine?
In the genetic code, a sequence of three nucleotide bases, known as a codon, specifies a particular amino acid. For Valine, there are four such codons. The genetic codons that specify Valine are GUU, GUC, GUA, and GUG. This redundancy means that multiple codons can result in the incorporation of Valine during protein synthesis.
