Rabbit Antibody to PC9 (paired basic amino acid cleaving enzyme-9, PCSK9, proprotein convertase subtilisin/kexin type 9a, NARC-1, neural apoptosis regulated convertase 1); Propeptide domain

RP1-PC9 is a rabbit polyclonal antibody made to the subtilisin-like serine protease PC9.  The antibody is made to a synthetic peptide based on the propeptide domain of human PC9. 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.

PC9 is the most recent of the human prohormone convertasae enzymes to be discovered. Also referred to as PCSK9 (proprotein convertase suntilisin/kexin type 9) and NARC-1 (neural apoptosis regulated convertase 1), PC9 is a member of the PC family of serine proteinases that cleaves after pairs of basic amino acids.PC9 and SKI-1 are two members of this larger family that do not have the paired basic amino acid requirement for cleavage. PC9 was first characterized as NARC-1, a gene up-regulated by neurons after serum withdrawal, and highly expressed in the liver and small intestine. Point mutations in PC9 were associated with autosomal dominant hypercholesteremia, and families were mapped with these different mutations (S127R and F216L in French families, D374Y in Utah and Norway). These mutations lead to increased cholesterol and LDL levels in serum, and decreased levels of LDL receptor on cell surfaces. Statin-type drugs that reduce cholesterol have been shown to upregulate PC9 expression, and thus PC9 seems to play a central regulatory role for cholesterol and LDL. Despite this, little is known about PC9 substrates. The catalytic domain has homology to other PC enzymes, the prohormone convertase family initially discovered for their role in processing POMC, insulin and other pro-hormones, and later found to process a wider range of precursor proteins. Some have renamed the prohormone convertases as proprotein convertases, and another group has renamed the entire family with a uniform nomenclature of SPCs (subtilisin-like proprotein convertases), with PC9 getting the SPC9 moniker. The PC9 structure contains a propeptide domain, a catalytic domain and an RGD containing cysteine-rich domain (homo-B). The mouse and rat sequences retain the RGD sequence, while the human and chimp sequences are modified to RGE, and the shorter PC9 sequence diverges just before the RGD sequence. The PCs have an RxxR consensus cleavage requirement, and the propeptides of the other PCs are separated from the mature protein by just such a sequence, but not so in PC9. Two forms of human PC9 are known to date; a 692 amino acid form, and a 578 amino acid form. The sequences differ in the C-terminal segment, after the catalytic domain. The 692 amino acid form has a predicted mass of 74.49 kDa, and a pI of 6.09, but glycosylation and other post-translational modifications make the pre-pro PC9 run at 78-80 kDa, the mature PC9 at 58 kDa. Smaller cleavage products are also detected. The RP1PC-9 epitope crosses the propeptide cleave site, and detects both the zymogen and active PC9. 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. 

FOR RESEARCH USE ONLY. NOT FOR USE IN HUMANS.

The undiluted antibody solution is stable for approximately 12 months at -20°C.

Triple Point Biologics products are sold exclusively through Abcam. For availability, pricing and buying information please select your country below and press 'Go'. You will be relocated to the relevant datasheet page on Abcam's website.