Aspartyl Aminopeptidase (ASPEP)

ASPEP is an aminopeptidase which prefers acidic amino acids, and specifically favors aspartic acid over glutamic acid. It is thought to be a cytosolic protein involved in general metabolism of intracellular proteins.The deduced 490-amino acid human protein has a calculated molecular mass of approximately 52 kD and shares similarity with S. cerevisiae aminopeptidase I, a zinc metalloproteinase found in the vacuole. Sequence analysis of the DNPEP protein in various species revealed several conserved residues including 3 histidines, 3 glutamates, and 5 aspartates. Northern blot analysis of rat tissues detected a 1.9-kb Dnpep transcript in all tissues examined, with highest expression in testis, intermediate expression in kidney and lung, and lesser but significant expression in spleen, liver, and brain.