Description
RP2-Serpin-B12 is a polyclonal antibody made to the serine proteinase inhibitor serpin-B12. The antibody is made to a synthetic peptide based on the reactive center loop area of human serpin-B12. 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-B12 is a serine proteinase inhibitor of the ovalbumin-like B clade of serpins. Serpin-B12 was first discovered in BLAST searches of the human genome, looking for analogs of the serpin family. Serpin-B12 was found by PCR to be widely distributed in the human brain, bone marrow, tonsil, heart, liver, lung, spleen, pancreas, kidney, ovary, placenta and testis. Serpin-B12 inhibits trypsin at low nanamolar efficiencies, plasmin, and cathepsin G at 500-800 nanamolar efficiencies, and uPA at micromolar concentrations. 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-B12 is Arg390-Ser391 of the 425 amino acid sequence. The original sequence described was 405 amino acids in length, with predicted mass of 46.3 kDa and pI of 5.21. Splice variants of 425 and 183 amino acids have been reported, with predicted masses of 48.4 and 20.9 kDa respectively, and pIs of 5.08 and 5.52 respectively. The 405 and 425 amino acid forms share the same aminoterminus. The 405 amino acid form has a deletion in residues 82-102, of the 425 amino acid form. The 183 amino acid form starts at the third methionine, relative to the longer forms. All three forms contain the reactive center loop of the long form, but it is unknown if the shorter forms are active serpins. RP2-Serpin-B12 recognizes all of the listed forms of serpinB12. 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.
