Myeloperoxidase (MPO) is a heme-containing enzyme belonging to the XPO subfamily of peroxidases. It is an abundant neutrophil and monocyte glycoprotein that catalyzes the hydrogen peroxide-dependent conversion of chloride, bromide, and iodide to multiple reactive species (1). Post-translational processing of MPO involves the insertion of a heme moiety and the proteolytic removal of both a propeptide and a 6 aa internal peptide (2). This results in a disulfide-linked dimer composed of a 60 kD heavy and 12kD light chain that associate into a 150 kD enzymatically active tetramer. The tetramer contains two heme groups and one disulfide bond between the heavy chains (2). Alternate splicing generates two additional isoforms of MPO, one with a 32 aa insertion in the light chain, and another with a deletion of the signal sequence and part of the propeptide (3). Human and mouse MPO share 87% aa sequence identity. MPO activity results in protein nitrosylation and the formation of 3-chlorotyrosine and dityrosine crosslinks (4-6). Modification of ApoB100, as well as the lipid and cholesterol components of LDL and HDL, promotes the development of atherosclerosis (5, 7-9). MPO is also associated with a variety of other diseases (1), and inhibits vasodilation in inflammation by depleting the levels of NO (10). Serum albumin functions as a carrier protein during MPO movement to the basolateral side of epithelial cells (11). MPO is stored in neutrophil azurophilic granules. Upon cellular activation, it is deposited into pathogen-containing phagosomes (2). While mice lacking MPO are impaired in clearing select microbial infections, MPO deficiency in humans does not necessarily result in heightened susceptibility to infections (12, 13).
Source:Human CD33 Signal Peptide (Met 1-Ala 16), Human Myeloperoxidase (Ala 49-Ser 745), HHHHHHHHHH; A DNA sequence encoding the signal peptide from human CD33 joined with the human Myeloperoxidase (Ala 49-Ser 745; Accession # P05164) was fused with a 10x histidine tag at the C-terminus. The chimeric protein was expressed in a mouse myeloma cell line, NS0.
Molecular Mass:The recombinant human Myeloperoxidase starts at Ala 49 and has a calculated molecular mass of approximately 80kD. As a result of glycosylation, the protein migrates as an ~80-90 kD protein in SDS-PAGE under reducing conditions. In gel filtration chromatography, the recombinant protein migrates as a tetramer.
Activity:Measured by its ability to oxidize guaiacol in the presence of hydrogen peroxide (Desser, R.K., et al. 1972 Arch.Biochem. Biophys. 148: 452-65). See Activity Assay Protocol on next page for details. The specific activity of the recombinant human Myeloperoxidase is > 5000 pmoles/min/ug as defined in the assay.
Storage and Stability:Lyophilized powder may be stored at -20/-70°C. Reconstitute to nominal volume by adding ddH20 and 0.1% BSA or HSA . Aliquot and store at -20/-70°C. Reconstituted product is stable for 3 months at -20/-70°C. 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.
仕様
Size：250ug
Source Antigen：Recombinant, NS0 cells
Grade：Purified
Purity：≥90%, as determined by SDS-PAGE and visualized by silver stain. Endotoxin:≤1EU/1ug (LAL).
Form：Supplied as a lyophilized powder from 20mM Tris, 150mM sodium chloride, pH 7.5. Reconstitute with ddH20 and 0.1% BSA or HSA to 0.5-1mg/ml.
