The structures of glycine and alanine are given below. Show the peptide linkage in glycylalanine.
$H_2N-CH_2-COOH$ (glycine);
$H_2N-CH(CH_3)-COOH$ (alanine)

(N/A) In glycylalanine,the peptide linkage is formed by the reaction between the carboxyl group $(-COOH)$ of glycine and the amino group $(-NH_2)$ of alanine,with the elimination of a water molecule $(H_2O)$.
The reaction is:
$H_2N-CH_2-COOH + H_2N-CH(CH_3)-COOH \rightarrow H_2N-CH_2-CO-NH-CH(CH_3)-COOH + H_2O$
The group $-CO-NH-$ is the peptide linkage.