Explanation

Erepsin, trypsin and pepsin are proteolytic enzymes. $Polypeptides\ + \ Oligopeptides\ \underset{Amino\ peptidase}{\overset{\ \ \ \ \ \ \ \ \ \ \ \ \ Erepsin\ \ \ \ \ \ \ \ \ \ \ \ \ }{\rightarrow}}Amino\ acids$ $Trypsinogen\ \underset{Autocatalysis}{\overset{\ \ \ \ \ \ \ \ \ \ \ Trypsin\ \ \ \ \ \ \ \ \ \ }{\rightarrow}}Trypsin$ $Proteins + Peptones\ \overset{\ \ \ \ \ Pepsin\ \ \ \ \ }{\rightarrow}\ Polypeptides + \ Oligopeptides$