Question

Give the name of the amino acid represented by each of the following three- letter abbreviations: a. Ala b. Val c. Lys d. \(\mathrm{Cys}\)

Short answer

Ala: Alanine, Val: Valine, Lys: Lysine, Cys: Cysteine

Step-by-step solution

Identify Ala

Ala stands for Alanine. This amino acid is non-polar and hydrophobic.

Identify Val

Val stands for Valine. Valine is also non-polar and hydrophobic.

Identify Lys

Lys stands for Lysine. This amino acid is basic and positively charged at physiological pH.

Identify Cys

Cys stands for Cysteine. It contains a thiol group and can form disulfide bonds, contributing to protein structure.

Key concepts

Alanine

Alanine, represented by the three-letter abbreviation 'Ala', is a crucial amino acid within the body. It's classified as non-polar and hydrophobic, which means it does not interact well with water. Alanine plays an important role in metabolism, as it is involved in the glucose-alanine cycle. This cycle helps in transferring nitrogen from muscles to the liver, where it can be converted into urea. Additionally, alanine stabilizes regions of proteins by forming tight turns in their structures.
Alanine can be found in various foods such as meat, fish, eggs, and dairy products.

Valine

Valine, indicated by 'Val', is another important amino acid. Like alanine, it is non-polar and hydrophobic. Valine is one of the three branched-chain amino acids (BCAAs), along with leucine and isoleucine. These BCAAs play a crucial role in muscle metabolism and are vital for muscle growth, tissue repair, and energy production.
Valine is essential, meaning it needs to be obtained from the diet since the body cannot synthesize it. Good dietary sources of valine include dairy products, meat, soy products, beans, and legumes.

Lysine

Lysine, abbreviated as 'Lys', is a basic amino acid and carries a positive charge at physiological pH. This positive charge is due to its amino group in the side chain. Lysine is essential, meaning our bodies cannot produce it, so it must be taken in through the diet. Lysine is crucial for protein synthesis, hormone production, enzyme synthesis, and the absorption of calcium.
Furthermore, lysine has antiviral properties and helps in the production of carnitine, a nutrient responsible for converting fatty acids into energy. Rich sources of lysine include red meat, poultry, cheese, and nuts.

Cysteine

Cysteine, noted as 'Cys', is a unique amino acid due to its thiol group (-SH). This thiol group allows cysteine to form disulfide bonds with other cysteine molecules, stabilizing protein structures. These bonds are integral in maintaining the shape of proteins such as insulin and antibodies.
Cysteine is semi-essential, which means it can be synthesized in the body but might need to be consumed in the diet during certain life stages or under specific conditions. Sources of cysteine include poultry, eggs, red bell peppers, garlic, and onions.
These disulfide bonds also play a crucial role in the structural stability and function of proteins, impacting their overall biological activity.