Major histocompatibility complex
Aminopeptidases hydrolyze N-terminal amino acids of proteins or peptide substrates. Major histocompatibility complex (MHC) class I molecules rely on aminopeptidases such as ERAP1 and LRAP to trim precursors to antigenic peptides in the endoplasmic reticulum (ER) following cleavage in the cytoplasm by tripeptidyl peptidase II (TPP2).