Oligopeptidase B (EC 3.4.21.83, protease II, Escherichia coli alkaline proteinase II) is an enzyme. This enzyme catalyses the following chemical reaction Oligopeptidase B (EC 3.4.21.83, protease II, Escherichia coli alkaline proteinase II) is an enzyme. This enzyme catalyses the following chemical reaction This enzyme is present in Escherichia coli.