| Description | Background information Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS). Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its Background information Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS). Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric distribution across the phospholipid bilayer and is translocated to the extracellular membrane leaflet marking cells as targets of phagocytosis. Once on the outer surface of the membrane, PS can be detected by fluorescently labeled Annexin V in a calcium-dependent manner.In early-stage apoptosis, the plasma membrane excludes viability dyes such as propidium iodide (PI), 7-AAD. These cells will stain with Annexin V but not a viability dye, thus distinguishing cells in early apoptosis. However, in late stage apoptosis, the cell membrane loses integrity thereby allowing Annexin V to also access PS in the interior of the cell. A viability dye can be used to resolve these late-stage apoptotic and necrotic cells (Annexin V, viability dye-positive) from the early-stage apoptotic cells (Annexin V positive, viability dye-negative). We offer recombinant Annexin V conjugated to a numerous fluorophores, as well as an Annexin V biotin conjugate which can be detected with fluorophore-labeled streptavidin. By binding to PS, fluorophores labeled Annexin V can be used to detect and quantify apoptotic cells via flow cytometry or fluorescence microscopy. The excitation and emission maxima of the Annexin V conjugates are summarized in the following table. Cat.No.Ex/Em (nm)Format1rp226056NABiotin2rp225998343/441AF3503rp225999401/422AF4054rp226057490/525AF4885rp226001590/618AF5946rp226060650/668AF6477rp226002681/704AF6808rp226003752/776AF7509rp226053498/517FITC10rp226004410/455Pacific Blue11rp226006647/665Cy512rp226054650/660APC13rp226055565/575PE14rp226058565/670PE-Cy515rp226059565/774PE-Cy7Precautions1. Please try to avoid light when using to slow down the quenching of fluorescence.2. Propidium Iodide Solution is toxigenic and mutagenic; handle with care.3. Due to the calcium dependence of the Annexin V:PS interaction, it is critical to avoid buffers containing EDTA or other calcium chelators during Annexin V experiments.Instruction for use1. Dilute 10X Binding Buffer (A1372288) to 1X using distilled water (1 mL 10X Binding Buffer + 9 mL ddH2O).2. Wash cells twice with cold PBS and then resuspend the desired amounts of cells in Annexin V Binding Buffer at a concentration of 1.0-5.0 x 106 cells/mL.3. Add 5 µL of Annexin V-AF350 to 100 µL of the cell suspension. Stain with a viability dye, such as PI (P1373641; P1372285), 7-AAD (A1372406), or DAPI (D1372407) dyes, if desired.4. Gently vortex the cells and incubate for 10 min at RT (25°C) in the dark.5. Add 100 µL of 1X Binding Buffer to each assay. Analyze by flow cytometry within 1 hr... Read More | Inquire | Inquire | Inquire | Carboxypeptidase B catalyzes hydrolysis of the basic amino acids lysine, arginine and histidine from theC-terminal end of polypeptides. The molecular weight is 34,500 daltons, the pH optimum is 8.0, and pI is 6.0.Carboxypeptidase B is competitively inhibited by arginine and lysine. The enzyme is Carboxypeptidase B catalyzes hydrolysis of the basic amino acids lysine, arginine and histidine from theC-terminal end of polypeptides. The molecular weight is 34,500 daltons, the pH optimum is 8.0, and pI is 6.0.Carboxypeptidase B is competitively inhibited by arginine and lysine. The enzyme is also inhibited by metal chelating agents, e.g., EDTA. Recombinant Carboxypeptidase B (EC 3.4.17.2) is expressed in E.Coli and purified by high pressure liquid chromatography. There is no trace of other enzyme (such as carboxypeptidase A and chymotrypsin) activity. No protease inhibitors such as PMSF are present in the preparation.Animal origin free:eliminate the risk of virus presence, or of any other potential adventitious agents found in animal-derived carboxypeptitase B.Stability:A sterile recombinant carboxypeptidase B lyophilized eliminates the risk of contamination and decreases the chances of activity loss in the process of transport and storage. High purity:1) Recombinant carboxypeptidase B provides increased specific activity and eliminates contaminating protease activities found in extracted enzymes with lower purity level. 2) No other contaminating proteases such as chymotrypsin and carboxypeptidase A. 3）Less than 10ppm of recombinant trypsin... Read More |