Question

Calculate the number of possible pentapeptides that contain one residue each of$\mathbf{\text{Ala, Gly, His, Lys,}}$ and $\mathbf{\text{Val}}$.

Short answer

The number of possible pentapeptides that contain one residue each of $\text{Ala, Gly, His, Lys,}$ and$\text{Val}$ is 120.

Step-by-step solution

Concept Introduction

Pentapeptide repeats are a type of sequence pattern present in protein molecules in multiple tandem copies.Pentapeptide repeat proteins are found in all organisms, but cyanobacterial genomes have more copies.

The number of Pentapeptides

The first residue can be one of the five residues then the second residue can be one of the four, the third residue can be one of the remaining three, the second can be one of the remaining two, and the fifth one is the last residue.

The solution is obtained as $\text{N = 5! = 120}$.

Therefore, the number is obtained as 120 .