Question

Which of the following Aminoacids can be used in the prepration of dipeptide? (a) CC(N)C(=O)O (b) \(\mathrm{H}_{2} \mathrm{~N}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{COOH}\) (c) CC(N)CC(=O)O (d) NCC(=O)O

Short answer

All options (a), (b), (c), and (d) can be used to prepare dipeptides.

Step-by-step solution

Understanding Dipeptides

Dipeptides are formed when two amino acids join together through a peptide bond. This bond forms between the amine group of one amino acid and the carboxyl group of another. Thus, amino acids suitable for dipeptide formation must possess both an amine group (-NH2) and a carboxyl group (-COOH) in their structure.

Analyze Option (a)

Analyze the SMILES representation: "CC(N)C(=O)O". This corresponds to alanine, which has a carboxyl group (-COOH) and an amine group (-NH2) as part of its structure, making it suitable for dipeptide formation.

Analyze Option (b)

For the option \( \mathrm{H}_{2} \mathrm{~N}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{COOH} \) , there is an amine group and a carboxyl group. Thus, this structure, representing 4-aminobutyric acid (GABA), can be used in the preparation of a dipeptide.

Analyze Option (c)

Analyze the SMILES representation: "CC(N)CC(=O)O". This corresponds to valine, which has both an amine group and a carboxyl group, making it suitable for dipeptide formation.

Analyze Option (d)

Analyze the SMILES representation: "NCC(=O)O". This represents glycine, which also has both an amine group and a carboxyl group, and can form dipeptides.

Key concepts

Amino Acids

Amino acids are the building blocks of proteins. They play a critical role in all biological processes. Each amino acid has a central carbon atom, known as the alpha carbon, which is bonded to four different groups: an amine group (-NH₂), a carboxyl group (-COOH), a hydrogen atom, and a side chain that is unique to each amino acid.

Here are some key features of amino acids:

• Structural Units: The structure of amino acids allows them to link together, forming chains known as peptides.
• 20 Standard Amino Acids: There are 20 standard amino acids in proteins, each with unique properties and side chains.
• Role in Protein Synthesis: They are crucial for the construction and function of proteins in the body.

In terms of dipeptide formation, two amino acids must possess both an amine group and a carboxyl group in their structure.

Peptide Bond

The peptide bond is a covalent bond that connects two amino acids. This connection forms when the amine group of one amino acid reacts with the carboxyl group of another amino acid, releasing a molecule of water in a process called condensation. This reaction joins the two amino acids, facilitating the formation of larger protein structures.

Here’s how peptide bonds establish the backbone of proteins:

• Condensation Reaction: The reaction involves the removal of a water molecule, creating a bond between the carbon atom of the first amino acid and the nitrogen atom of the second.
• Stability: Peptide bonds are stable, requiring a significant amount of energy to break them, which is why proteins are robust structures.
• Flexibility: The bonds allow rotation around the adjacent atoms, giving proteins their complex and versatile shapes.

Understanding peptide bonds is pivotal in grasping the principles of protein structure and function.

Amine Group

The amine group is a functional group with the formula -NH₂. It is crucial in the structure of amino acids—a primary component that facilitates bonding with other molecules.

The amine group has the following characteristics:

• Basic Nature: The amine group can accept protons, making it basic and an important participant in chemical reactions.
• Participation in Peptide Bonds: The nitrogen atom in the amine group is essential for forming peptide bonds with the carboxyl group of another amino acid.
• Presence in Proteins: This group is found in all amino acids that construct proteins, ensuring their ability to link together.

The presence of an amine group in amino acids is vital for protein synthesis and dipeptide formation.

Carboxyl Group

The carboxyl group is represented by -COOH, and it is an essential functional group in biochemistry, especially in amino acids. It's responsible for the acidic properties of amino acids and plays a crucial role in forming peptide bonds.

Some important points regarding the carboxyl group include:

• Acidic Nature: The carboxyl group can donate a proton (H⁺), making it acidic and reactive in forming covalent bonds.
• Key in Peptide Bonds: This group combines with the amine group of another amino acid, which is essential for the peptide bond formation that constructs protein chains.
• Contribution to Polarity: The carboxyl group also contributes to the overall polarity and solubility of amino acids, impacting their behavior in biological systems.

Thus, the carboxyl group is integral to the chemical characteristics of amino acids, enabling the formation of dipeptides and proteins.