ARMSP-2 (Recombinant)

Frequently Asked Questions

What molecular weight band should I expect for ARMSP-2 recombinant protein on SDS-PAGE or Western blot?

The native ARMS2 protein is 107 amino acids, giving a predicted molecular weight of approximately 12 kDa. On SDS-PAGE under reducing conditions, the recombinant (REC-ARMSP2) produced in HEK293 cells typically migrates at 12–14 kDa. Minor upward shifts from any affinity tag or post-translational modifications introduced during mammalian expression are possible. Confirm purity visually — >90% by Coomassie staining is expected. When using RP-ARMSP2 for Western blot detection of this band, expect a clean signal in this low-MW range with minimal background at recommended antibody dilutions.

Does recombinant ARMSP-2 represent the full-length protein or a processed isoform?

REC-ARMSP2 covers the full 107-amino-acid sequence of human ARMS2 (UniProt P0C7Q2). No truncations or isoform-specific splicing have been introduced. Because this recombinant is expressed in HEK293 mammalian cells, it undergoes human-compatible post-translational processing, making it a closer structural proxy to the endogenous retinal protein than bacterially expressed material would be. This is particularly relevant for researchers studying protein–protein interactions or using the recombinant as an antibody validation standard, where conformational fidelity to the native form matters.

Does ARMSP-2 have known enzymatic activity or a defined substrate for activity assays?

ARMS2 has no assigned enzymatic activity in current literature — its molecular function remains under active investigation, and no consensus substrate has been established. REC-ARMSP2 is therefore not intended for classical enzyme activity assays. Its primary in vitro utility is as a well-characterised recombinant antigen: positive control for Western blot, dot-blot sensitivity calibration, IHC optimisation, and as a binding partner in pull-down or co-immunoprecipitation experiments designed to probe ARMS2 protein–protein interactions. Researchers designing functional assays should treat any observed activity as exploratory.

What buffer conditions are recommended for ARMSP-2 recombinant protein in pull-down or binding assays?

REC-ARMSP2 is supplied in 50 mM Tris-HCl pH 7.5, 150 mM NaCl, 10% glycerol — a physiologically compatible formulation suitable for most binding and pull-down experiments without buffer exchange. If your assay requires lower glycerol (e.g., for SPR or BLI), dialysis or dilution into a matched Tris-NaCl buffer at pH 7.4–7.5 is appropriate; keep glycerol above 5% if the diluted protein will be stored before use. Avoid repeated freeze-thaw cycles — single-use aliquots are strongly recommended to preserve protein integrity across experiments.

What starting concentration of ARMSP-2 recombinant should I use for a dot-blot sensitivity check?

For an initial dot-blot sensitivity titration with the matched antibody RP-ARMSP2, a useful starting range is 50–500 ng of REC-ARMSP2 per spot. Begin at 250 ng and titrate down in threefold steps to identify your antibody's detection limit. Because the ARMS2 protein is small (~12 kDa), signal intensity can drop quickly at low loads — establishing this sensitivity threshold before moving to cell lysate experiments saves significant optimisation time. Endotoxin levels are <0.1 EU/µg by LAL, so background signal in functional binding assays should remain low.

Can I use REC-ARMSP2 as a positive control antigen for Western blot with the matched RP-ARMSP2 antibody?

Yes — this is a primary validated use case. Load 50–200 ng of REC-ARMSP2 per lane alongside your cell or tissue lysates. Run on a 12–15% polyacrylamide gel to resolve the ~12–14 kDa band cleanly, then blot and probe with RP-ARMSP2 (see /anti-armsp-2-rabbit-polyclonal-antibody for recommended dilutions). The recombinant and antibody are produced from the same target sequence in the same lab, so antigen–antibody compatibility is guaranteed — no cross-reactivity ambiguity. This pairing is directly useful for titrating primary antibody concentration and confirming specificity before committing to experimental samples.

How much ARMSP-2 recombinant protein should I load for Western blot positive control with RP-ARMSP2?

A load of 100 ng per lane is a reliable starting point for Western blot positive control when detecting with RP-ARMSP2. If your gel system resolves small proteins efficiently (12–15% acrylamide, Tris-tricine format recommended for sub-15 kDa targets), you can reduce this to 50 ng once the antibody dilution is optimised. Loading too little of a small protein like ARMSP-2 risks a faint or absent band, particularly if transfer efficiency for low-MW proteins has not been separately validated. Run the recombinant lane adjacent to a molecular weight ladder with clear 10–15 kDa markers.

How should I store and handle ARMSP-2 recombinant protein to maintain stability long-term?

Store REC-ARMSP2 at -20°C in single-use aliquots immediately upon receipt. The supplied buffer — 50 mM Tris-HCl pH 7.5, 150 mM NaCl, 10% glycerol — provides cryoprotection, but repeated freeze-thaw cycles will progressively degrade a small protein like ARMSP-2. Aliquot to your typical working volume (e.g., 5–10 µg per tube) before first use. Once thawed, keep on ice and use within the same working session. Avoid storage in standard -20°C frost-free freezers that cycle temperature. Under correct conditions, stability is expected for 12 months from date of receipt.