Analysis of a hexapeptide using enzymatic cleavage reveals the following result:
- Amino acid composition of the peptide is: $2R, A, V, S, Y$
- Trypsin digestion yields two fragments and the compositions are: $(R A,V)$ and $(R, S, Y)$
- Chymotrypsin digestion yields two fragments and the compositions are: $(A, R, V, Y)$ and $(R, S)$
- Digestion with carboxypeptidase A yields no cleavage product.
Given: Trypsin cleaves at carboxyl side of $R$.
Chymotrypsin cleaves at carboxyl side of $Y$.
Carboxypeptidase $A$ cleaves at amino side of the $C$-terminal amino acid (except $R$ and $K$) of the peptide.
The correct amino acid sequence of the peptide is
- $\text{RSYRVA}$
- $\text{AVRYSR}$
- $\text{SRYVAR}$
- $\text{SVRRYA}$