A tetrapeptide has -COOH group on alanine. This produces glycine (Gly), Valine (Val), Phenyl alanine (Phe) and Alanine (Ala) on complete hydrolysis. For this tetrapeptide, the number of possible sequences (primary structures) with -NH 2 group attached to a chiral center is

Question

Aicharya · Accepted Answer

Following combinations are possible for tetrapeptide:

\begin{matrix} Val - Phe - Gly - Ala \\ Val - Gly - Phe - Ala \\ Phe - Gly - Val - Gly \\ Phe - Val - Gly - Ala \end{matrix}

In all above sequences, C-terminal is alanine.
Glycine is optically inactive amino acid, it can not be N-terminal. Hence, only above combinations are possible.

A tetrapeptide has -COOH group on alanine. This produces glycine (Gly), Valine (Val), Phenyl alanine (Phe)…

Solution