Cytosol aminopeptidase

LAP3 (cytosol aminopeptidase) is a zinc-dependent metallopeptidase that removes N-terminal hydrophobic amino acids from various peptides (UniProt: P28838). The enzyme's activity is modulated by metal cofactors; in the presence of manganese, it exhibits specific activity toward cysteine-glycine conjugates. LAP3 participates in glutathione metabolism and the degradation of glutathione S-conjugates, processes implicated in cellular redox homeostasis regulation.

LAP3 is primarily localized to the cytosol and is involved in peptide catabolism and antioxidant metabolism. The UniProt record lists no specific disease associations in the baseline annotation (UniProt: P28838).

In Alzheimer's Disease, LAP3 is upregulated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of 0.68 (Chaparral AD proteomics). This upregulation was detected across a subcellular fractionation study of human AD brain using TMT-labeled tandem mass spectrometry, suggesting potential involvement in AD-associated proteostatic or redox-regulatory mechanisms.