Question

What is the equation for formation of dipeptide?

Answer 1

Hint: Amino acids are found in the human body, which are the simplest unit of proteins. When 2 amino acids link together they form a di – peptide bond. It is a type of condensation reaction, where the peptide bond is formed by removal of a water molecule. These bonds consist of an amide linkage.

Complete answer:
Amino acids are the simplest unit of proteins; they contain an amine group and a carboxylic acid group and hence called amino acids. When two amino acids combine together, they form a bigger network of amino acids. The linkage in the combination of amino acids is through a peptide bond that has a$\left( -\overset{O}{\mathop{\overset{||}{\mathop{C}}\,}}\,-NH \right)$ linkage called as peptide or amide linkage. This linkage is a result of condensation of 2 molecules of amino acids that lose a water molecule to form dipeptide. A dipeptide consists of 1 peptide linkage. The equation for formation for dipeptide is as follows:

Here, two amino acids having any alkyl group R, combine together and lose a water molecule to form as dipeptide.
The most common example of a dipeptide formation is combination of glycine and alanine as:
$\begin{align}
  & {{H}_{2}}N-C{{H}_{2}}-COOH+{{H}_{2}}N-\overset{C{{H}_{3}}}{\mathop{\overset{|}{\mathop{CH}}\,}}\,-COOH\xrightarrow{-{{H}_{2}}O}{{H}_{2}}N-C{{H}_{2}}-\overset{O}{\mathop{\overset{||}{\mathop{C}}\,}}\,-NH-\overset{C{{H}_{3}}}{\mathop{\overset{|}{\mathop{CH}}\,}}\,-COOH \\
 & \,\,\,\,\,\,\,\,\,\,glycine\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,alanine\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,glycylalanine \\
\end{align}$
Hence, the reaction equation of dipeptide formation involves condensation and removal of water molecules as depicted above.

Note:
When 3 amino acids combine together then a tripeptide is formed that consist of 2 peptide linkages. When more than 10 amino acids join together then they are called polypeptides. The combination of more than 100 amino acids joined together forms a protein. Amino acids can be neutral, acidic or basic.