<p> Members of this family represent a distinctive subset within the zinc metallopeptidases of MEROPS peptidase family M1 (aminopeptidase N, clan MA). This entry represents leukotriene A-4 hydrolase (LTA4), which has both epoxide hydrolase and aminopeptidase activity at the same active site. The physiological substrate for aminopeptidase activity is not known [<cite idref="PUB00017074"/>].</p>