Vendor: Triple Point Biologics, Inc.
RP2-Serpin-B is a polyclonal antibody made to the serine proteinase inhibitor PI-9. The antibody is made to a synthetic peptide based on the reactive center loop area of human serpin-B9. The antibody has been peptide-affinity purified, concentrated to 1.0 mg/ml, with the addition of 0.05% sodium azide as preservative and 50% glycerol as cryoprotectant.
Serpin-B9, also known as CAP3, Cytoplasmic Antiproteinase-3, and PI-9, Proteinase Inhibitor-9, is a serine proteinase inhibitor of the ovalbumin-like B clade of serpins. The mouse orthologue to PI-9 is SPI-6. Serpin-B9 was first discovered in human bone marrow in a search for serpins similar to serpin-B6. Serpin-B9 was identified in lymphocytes, especially natural killer cells and cytotoxic T lymphocytes, cells which also produce and store the apoptosis-inducing enzyme Granzyme-B. PI-9 was shown to be a potent inhibitor of Granzyme-B, working at picamolar efficiencies. PI-9 was also shown to inhibit caspase-1, the interleukin-1 converting enzyme, thus blocking IL-1(beta) production, and decreasing inflammatory processes. Most leukemia cells and many tumor cells produce PI-9, leading to speculation that PI-9 may help protect tumor cells from destruction by NK and CTL cells. PI-9 is also found in placenta, lung, kidney, mast cells, and many tissues and cell lines. In kidney transplant, PI-9 is sharply elevated, and in the liver PI-9 has been shown to be up-regulated by a downstream estrogen promoter. Serpin-B9 inhibits Granzyme-B, and is cleaved by Granzyme-M, as a down regulatory step. Serpin-B9 also inhibits the bacterial proteinase subtilisin-A, and this may be a protective agent against infections. Neutrophil elastase is also a target of serpin-B9. Like serpin-B6 and serpin-B8, serpin-B9 lacks a signal sequence, and is found mainly in the cytoplasm and nucleus, although it can be detected outside of cells and in serum. Most of the serpins (SERine Proteinase Inhibitors) are serine proteinase inhibitors; although not all serine proteinase inhibitors are serpins, and visa versa. The overall structural shape of the B clade of serpins most resembles ovalbumin, which is not considered to be a serine proteinase inhibitor. The serpins share a reactive center loop motif: a substrate bait loop which, when cleaved, confers a remarkable molecular shift in the serpin molecule, and traps the enzyme. This mousetrap method works because the uncleaved serpin molecule is in tension, and cleaving the loop allows a more energetically favorable state to exist. The cleavage site in serpin-B9 is Glu340-Cys341 of the 379 amino acid sequence. The original sequence described was 379 amino acids in length, with predicted mass of 42.4 kDa and pI of 5.51. A recommended starting concentration for Western blots is 1:1,000 when using colorimetric substrates such as BCIP/NBT, and 1:5,000 for chemiluminescent substrates. Higher concentrations of antibody may be needed for samples from more distantly related species FOR RESEARCH USE ONLY; NOT FOR USE IN HUMANS.
The undiluted antibody solution is stable for approximately 12 at -20C.