Corin (Recombinant)

Frequently Asked Questions

What is the expected molecular weight of recombinant Corin on SDS-PAGE and Western blot?

The full-length Corin polypeptide has a predicted molecular weight of ~117 kDa based on its 1,042-amino-acid sequence. Due to extensive N-linked glycosylation across the large extracellular domain — supported by the HEK293 mammalian expression system — the apparent molecular weight on reducing SDS-PAGE typically runs between 150–200 kDa. When using our matched antibody RP-Corin for Western blot, set your marker expectations accordingly and do not mistake the upward shift for degradation or aggregation.

What processing or isoform state is this recombinant Corin — is it the full-length zymogen or the active cleaved form?

This recombinant represents the extracellular protease-competent ectodomain of Corin, produced in HEK293 cells in an active, soluble form. Native Corin undergoes autocatalytic or corin-mediated activation involving cleavage of the propeptide; the recombinant is supplied as an activated preparation suited for direct use in enzymatic assays. It retains the frizzled-type cysteine-rich domain and LDL receptor-like repeats that support proper folding and substrate recognition. Confirm activation state for your specific lot via the included activity data sheet.

What substrates can I use to measure recombinant Corin endopeptidase activity in a fluorogenic assay?

Corin's primary physiological substrates are pro-ANP (pro-NPPA) and pro-BNP (pro-NPPB), cleaved at Arg residues to release bioactive ANP and BNP(1-32). For fluorogenic assays, peptide substrates derived from the pro-ANP cleavage site — such as internally quenched FRET peptides spanning the Arg98 cleavage site of human pro-ANP — are well-established. Chromogenic substrates with a P1 Arg are also compatible. Confirm substrate Km for your lot by running a substrate saturation curve before IC50 work, as glycosylation-dependent activity can introduce lot-to-lot Km variation.

What is the recommended assay buffer for recombinant Corin activity assays and does buffer pH significantly affect activity?

Corin serine protease activity is optimal near physiological pH. A standard assay buffer of 50 mM Tris-HCl pH 7.5, 150 mM NaCl is directly compatible with the storage buffer and avoids a dilution-induced pH shift. Activity drops measurably below pH 6.5 and above pH 8.5. Adding 0.01–0.05% BSA or 0.01% Tween-20 helps minimize adsorption at low enzyme concentrations. Avoid strong reducing agents such as DTT above 1 mM, as these can disrupt the disulfide-stabilized frizzled domain and reduce specific activity.

What starting concentration of recombinant Corin should I use for IC50 inhibitor screening assays?

For IC50 determination, titrate enzyme concentration to achieve a linear signal response and consume no more than 10–15% of substrate over the assay window — a common starting point is 1–5 nM Corin with substrate at roughly 10–20 µM (below Km). Because Corin's active-site accessibility can be influenced by its glycosylated extracellular scaffold, run a preliminary dose-response of enzyme concentration (0.5–20 nM) against a fixed substrate before committing inhibitor compound. This prevents substrate depletion artifacts that compress apparent IC50 values.

Can I use recombinant Corin as a Western blot positive control with the RP-Corin rabbit polyclonal antibody?

Yes — this is one of the primary intended uses of the pairing. REC-Corin and RP-Corin are produced and validated together in the same laboratory, guaranteeing epitope compatibility. Load 50–150 ng of REC-Corin per lane on a 6–8% SDS-PAGE gel; expect a broad band at 150–200 kDa under reducing conditions owing to glycosylation. RP-Corin is validated for Western blot and provides a clean positive control signal without background bands that complicate interpretation when working with cell lysates expressing endogenous Corin.

How much recombinant Corin should I load for a Western blot positive control lane, and at what antibody dilution does RP-Corin work best?

Load 50–150 ng of REC-Corin per lane; 100 ng is a reliable starting point that gives a strong signal without overloading. Use RP-Corin at 1:500–1:2,000 in 5% non-fat milk or BSA in TBST, with an overnight 4°C primary incubation. The matched pairing means you do not need to optimize epitope retrieval conditions separately for the recombinant versus tissue samples — both are recognized by the same antibody lot used in validation. Confirm secondary antibody compatibility (anti-rabbit HRP) before running alongside endogenous Corin from cardiac tissue lysates.

How should I store and handle recombinant Corin to preserve enzymatic activity, and what is its shelf life after thawing?

REC-Corin is supplied in 50 mM Tris-HCl pH 7.5, 150 mM NaCl, 10% glycerol and shipped on dry ice. Store at -20°C in single-use aliquots immediately upon receipt. Once thawed, keep on ice and use within 4–6 hours; do not refreeze. Under recommended storage, activity is stable for at least 12 months from the date of manufacture. Avoid diluting to below ~0.1 µg/mL in plain buffer without a carrier protein such as 0.1% BSA, as surface adsorption at low concentrations causes measurable activity loss within hours.