Leucyl-cystinyl aminopeptidase (LNPEP)

Leucyl-cystinyl aminopeptidase (LNPEP, also known as insulin-regulated aminopeptidase or IRAP) is a zinc-dependent type II transmembrane aminopeptidase found in multiple tissues, particularly endosomes and cell membranes. LNPEP cleaves a variety of peptide hormones—including oxytocin, vasopressin, angiotensin III, enkephalins, and others—regulating hormone activity, homeostasis in pregnancy, cognitive function, and blood pressure. LNPEP also plays a critical immune role by trimming peptides for MHC class I antigen presentation, especially in dendritic cells, and controls trafficking of the GLUT4 vesicle in response to insulin in adipose and muscle tissue. In the brain, LNPEP acts as the angiotensin IV receptor, modulating memory and neuroprotection pathways. Genetic variations in LNPEP are linked to inflammatory, autoimmune, metabolic, and neurodegenerative conditions. IRAP inhibitors are investigational agents being assessed for cognitive and neurological effects[1][2][3][5].

Other names

Insulin-regulated aminopeptidaseIRAPOxytocinasePlacental leucine aminopeptidaseCystinyl aminopeptidaseInsulin-responsive aminopeptidaseOTASEP-LAPCAPPLAPVasopressinaseAngiotensin IV receptor (AT4 receptor)

Enzyme inhibition (IRAP inhibitors block peptide hormone cleavage or angiotensin IV binding, possible cognitive enhancement) Agonism/antagonism at angiotensin IV receptor site (affects neuroprotection, cognition, vascular effects)