| An 18-aa peptide sequence within cytoplasmic N-terminus of mouse neprilysin (NEP) (1). The amyloid beta-peptide (Ab) of 39 to 43aa (Ab40, Ab42, Ab43) is constitutively produced in brain upon proteolysis of the b-amyloid precursor protein (APP). In the young and healthy humans, Ab is rapidly catabolized before it can be deposited in the brain. However, upon aging or the onset of familial Alzheimers Disease, alterations in either synthesis or degradation/clearance of Ab may contribute to amyloid depositions in the brain. Ab is susceptible to a number of in vivo and in vitro proteases like cathepsin-D and M-13 metalloproteases. The M-13 family includes several members of zinc-dependent proteases like damage-induced neuronal endopeptidase (DINE), product of phosphate regulating gene with homologies to endopeptidases on the X chromosome (PHEX), neutral endopeptidase 24.11 or neprilysin (NEP) and neprilysin-like proteases (NEPLs). NEPLs (alpha, -beta, gamma) arise from the alternative splicing of a single NELPS gene and show ~54% sequence homology. M13 members are generally type II transmembrane proteins consisting of a single polypeptide chain with Zinc binding HEXXH motif, a short cytoplasmic tail, a transmembrane segment and an extra-cytoplasmic domain containing the enzyme active site. NEP [variously termed as neutral endopeptidase-24.11 (NEP), neprilysin, enkephalinase, EC3.4.24.11, common acute lymphoblastic leukemia antigen (CALLA), CD10] is the key in vivo enzyme degrading biopeptides Ab, substance-P and enkephalin in brain, atrial natriuretic peptide, bradykinin and endothelin-1 in kidney. It is a 97kD ectoenzyme (mouse, rat, human 750-aa) with a large extracellular domain containing its catalytic site, which can degrade Ab on cell surface. NEP is ubiquitous but its high expression in brain is restricted to striatum, olfactory tubercle, substantia nigra, choroids plexes, endopeduncular nucleus, pontine nucleus, and cerebellum and in many peripheral tissues, particularly in brush-border membranes. The poor expression of NEP in the hippocampus and cerebral cortex is reflected in the selective deposition of Ab42 in these regions. NEP is also expressed in soluble form in human plasma and cerebrospinal fluid. NEP can degrade both synthetic and cell secreted Ab40 and Ab42 and may be a good therapeutic target for the treatment of Alzheimers disease. Applications: Suitable for use in ELISA and Antibody Blocking. Not suitable for Western Blot due to low MW. Other applications not tested. Recommended Dilution: ELISA: 1ug/ml to coat plates. Antibody Blocking: 5-10ug peptide. Optimal dilution determined by the researcher. Storage and Stability: May be stored at 4C for short-term only. For long-term storage, aliquot and store at -20C. Aliquots are stable for at least 6 months at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer. |
