Rabbit Antibody to Kallikrein-4 (PRSS17, KLK-L1, enamel matrix serine protease (EMPS1), Prostase); Kallikrein loop  

RP1-hK4 is a rabbit polyclonal antibody made to the serine proteinase kallikrein-4 (hK4).  The antibody is made to a synthetic peptide based on the Kallikrein loop area of human Kallikrein-4.  RP1-hK4 reacts with human Kallikrein-4, and does not react with the human kallikreins (hK1-15).  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.

Kallikrein-4 (hK4) was first described as enamel matrix serine proteinase-1, a serine protease involved in degradation of amelogenin during tooth development and tooth enamel turnover. Unlike another enamel processing enzyme, MMP-20, hK-4 is not restricted to dental tissues. Also described as prostase, and Kallikrein-Like-1 (KLK-L1), hK-4 was identified as a protein elevated in prostate and breast cancer tissues, and was at first thought to be more or less prostate-specific. Since then hK-4 has been identified in a range of normal and cancerous tissues and cell lines. Androgen response elements have been identified in hK-4 genes, and the hK-4 levels have been shown to be modified by androgens and estrogens, similar to hK3 (PSA). hK-4 has also been shown to activate pro-uPa by generating the two-chain form after cleavage of the one-chain form, and thus may participate in an enzyme activation cascade. The Kallikrein-4 signal sequence is thought to be insufficient to allow secretion of hK-4, and several reports indicate a predominately nuclear isolation. A GFP-tagged Kallikrein-4 message was over expressed in cell culture, and the GFP tag localized to the nucleus. Other authors have found hK-4 in culture media of tumor cells and in sera of cancer patients, and to be secreted as a recombinant protein, leading to some debate on the issue. The hK-4 structure differs from the Kallikrein 1-3 in having a shorter “kallikrein loop”, the sequence thought to impart specificity to the classical kallikreins. Endogenous inhibitors include kallistatin, protein-C inhibitor and α1-proteinase inhibitor, although hK-4 can be found complexed to a number of different proteinase inhibitors. Full length hK4 is a 254 amino acid protein, with predicted mass of 27 kDa and a pI of 4.52, but extensive glycosylation and other posttranslational modifications give Kallikrein an apparent mass of 30-32 kDa on SDS PAGE gels. Different splice variants of Kallikrein-4 encode for proteins of 195, 159 and 75 amino acids, with predicted masses of 20.6, 16.9 and 8 kDa respectively, although expression of the related proteins is unknown. 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 12 months at -20°C.

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