Aminopeptidase RNPEPL1 (MEROPS identifier M01.022) is an aminopeptidase with broad specificity and pH preference. RNPEPL1 preferentially cleaves methionyl, glutamyl or citrullinyl bonds, and is maximally active at pH 6.6 - 8.0. It is not inhibited by factors that inhibit aminopeptidase B. A number of splice variants of the human gene are known [].