Anti-MMP-3 Rabbit Polyclonal Antibody

Frequently Asked Questions

What molecular weight band should I expect for MMP-3 on Western blot?

MMP-3 is synthesized as a 57 kDa pro-enzyme (stromelysin-1 zymogen) comprising 477 amino acids. Upon activation in the extracellular matrix, proteolytic cleavage removes the N-terminal pro-domain, yielding the active form at approximately 45 kDa. In most cell lysates and conditioned media, you will detect both the pro-form and active form, depending on cellular activation state. Serum-starved fibroblasts or stimulated chondrocytes typically show enrichment of the zymogen, while samples treated with plasmin or organomercurial compounds favor the processed form. Always run a positive control lysate from stimulated cells to confirm band identity.

Does this antibody detect mouse MMP-3 or only human MMP-3?

This polyclonal antibody is validated for human MMP-3. Mouse reactivity is predicted but not yet validated in our hands. Human and mouse MMP-3 share approximately 82 percent sequence identity, with conservation highest in the catalytic domain. If working with mouse samples, we recommend testing at the standard 1:1000 dilution first, using recombinant mouse MMP-3 or lysate from LPS-stimulated mouse macrophages as positive controls. Include a human control in parallel to confirm specificity. Report your results; cross-species validation depends on epitope accessibility and post-translational context.

What is the recommended starting dilution for Western blot with this MMP-3 antibody?

Start at 1:1000 dilution in 5 percent non-fat milk or BSA in TBST for Western blot. This dilution is optimized for standard chemiluminescent detection with 20–40 micrograms total protein per lane. MMP-3 is a secreted protease, so conditioned media often yields stronger signal than whole-cell lysate; concentrate serum-free media 10- to 20-fold if needed. For low-abundance samples or short exposures, titrate upward to 1:500. Overnight incubation at 4 degrees Celsius typically improves sensitivity compared to one-hour room-temperature protocols. Always include a recombinant MMP-3 standard or known positive lysate.

Can this antibody distinguish between pro-MMP-3 and active MMP-3?

This antibody recognizes both the 57 kDa pro-enzyme and the 45 kDa active form, as the epitope spans a region retained after N-terminal cleavage. You will detect both forms on Western blot if they are present in your sample. To assess activation status, run reducing SDS-PAGE and quantify the ratio of the two bands. For functional assays requiring selective detection of active MMP-3, consider activation-state-specific antibodies or enzymatic assays. Most cell culture supernatants contain predominantly pro-MMP-3 unless exogenous activators such as trypsin, plasmin, or APMA are added.

What positive control samples work best for detecting MMP-3?

Human fibroblasts or chondrocytes stimulated with IL-1 beta or TNF-alpha for 24 to 48 hours robustly express MMP-3 in conditioned medium. HT-1080 fibrosarcoma cells constitutively secrete moderate levels. For tissue lysates, use arthritic cartilage, inflamed synovium, or wound-edge skin, where MMP-3 is upregulated during matrix remodeling. Recombinant human MMP-3 provides a defined standard; load 5 to 10 nanograms per lane. Avoid heavily serum-supplemented media as controls, since serum proteases can degrade or activate MMP-3, complicating interpretation. Always process positive controls in parallel with experimental samples.

Does MMP-3 require special sample preparation to prevent degradation or autoactivation?

Yes. MMP-3 is both a protease and a substrate for other MMPs, so rapid processing is critical. Lyse cells on ice in buffer containing protease inhibitor cocktail with EDTA or EGTA to chelate zinc and calcium, preventing autocatalytic activation. For conditioned media, add inhibitors immediately upon collection and store at minus 80 degrees Celsius in single-use aliquots. Avoid repeated freeze-thaw cycles, which can induce aggregation or cleavage. If studying MMP-3 activation, omit metalloproteinase inhibitors but work quickly and include time-zero controls to document baseline zymogen levels before induced processing occurs.

Can I use this antibody for immunohistochemistry on paraffin-embedded tissue?

Our antibodies are validated for IHC applications, including paraffin sections. For MMP-3, antigen retrieval is essential; citrate buffer pH 6.0 heat-induced epitope retrieval for 20 minutes typically works well. MMP-3 localizes to stromal fibroblasts, chondrocytes, and activated macrophages in inflamed or remodeling tissues, with occasional nuclear staining in virus-infected or stressed cells. Use 1:100 to 1:200 dilution as a starting point. Synovium from rheumatoid arthritis patients or healing wound tissue serve as informative positive controls. Include isotype-matched control IgG on serial sections to confirm specificity of stromal staining.

How should I store this MMP-3 antibody for long-term stability?

Store the antibody at minus 20 degrees Celsius in the supplied buffer. For extended stability beyond six months, aliquot into small volumes immediately upon receipt to minimize freeze-thaw cycles, which can reduce titer and increase aggregation. Avoid repeated thawing; each working aliquot tolerates up to three freeze-thaw cycles without significant loss of reactivity. If using frequently, prepare a working stock diluted 1:10 in PBS with 50 percent glycerol and 0.02 percent sodium azide; this remains stable at minus 20 degrees Celsius for at least 12 months. Do not store diluted antibody in TBST without preservative.