Description
RP2-Serpin-B2 is a polyclonal antibody made to the serine proteinase inhibitor PAI-2. The antibody is made to a synthetic peptide based on the reactive center loop area of human serpin-B2. 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.
Use
Serpin-B2, also known as PAI-2 (Plasminogen Activator Inhibitor-2) is a serine proteinase inhibitor of the ovalbumin-like B clade of serpins. Serpin-B2 was first discovered in the placenta, and given the name PAI-2 because of the ability to inhibit urokinase plasminogen activator (u-PA) at low micromolar efficiency. Serpin-B2 also inhibits tissue plasminogen activator (t-PA), but with micromolar efficiency, and PAI-1 is much more efficient that serpin-B2 on both forms of plasminogen activator. The structure of PAI-2 is not terribly similar to PAI-1, however, which is an E clade serpin. 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-B2 is Arg380-Thr381 for human PAI-2. Serpin-B2 is made by many cell types, and is found intracellularly as an unglycosylated kDa protein, and secreted as a 60 kDa protein. Serpin-B2 is found in saliva, secreted by gingival fibroblasts, and in the skin. Serpin-B2 levels are elevated in serum during pregnancy, and in leukemia, breast cancer and ovarian cancer, although it was lowered in some cancers. The full length serpin-B2 sequence encodes a 415 amino acid protein, with a predicted mass of 46.7 kDa, and a pI of 5.32. A shorter Serpin-B2 isoform of 382 amino acids, has been reported, with a predicted mass of 43.1 kDa and a pI of 5.69. The shorter form has a deletion just after the start of the mature protein, but it is unclear what the relative production and distribution is for the shorter sequence. RP1-Serine-B2 recognizes the 415 amino acid form of PAI-2, as well as the shorter form. 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.
Storage
The undiluted antibody solution is stable for approximately 12 at -20C.
