MMP-1 (Recombinant)

Frequently Asked Questions

What molecular weight band should I expect for recombinant MMP-1 on SDS-PAGE or Western blot?

Under reducing SDS-PAGE conditions, this HEK293-expressed recombinant MMP-1 typically runs at approximately 52–57 kDa — slightly above the theoretical 54 kDa of the processed proenzyme — owing to N-linked glycosylation added during mammalian expression. The latent proform (full-length minus signal peptide) is ~54 kDa; autocatalytic or APMA-activated enzyme loses the ~10 kDa propeptide to yield a ~44–46 kDa active species. If you are running the protein before activation, expect the higher band. Run alongside a broad-range MW ladder and include an APMA-treated lane to distinguish pro- versus active forms.

Which isoform or processing form is this recombinant MMP-1 — proenzyme or active enzyme?

The product is supplied as the active enzyme form: the propeptide has been removed during production and quality control processing in HEK293 cells. The catalytic domain and C-terminal hemopexin-like domain (residues ~100–469 of the full-length sequence, post signal peptide cleavage) are both present, preserving the substrate-specificity determinants required for fibrillar collagen recognition. This is particularly relevant if you need the hemopexin domain for collagen-binding or protein–protein interaction assays — truncated catalytic-domain-only constructs produced in E. coli would lack this region.

What substrates and assay conditions should I use to confirm MMP-1 activity in a fluorescent peptide assay?

A standard choice is the fluorogenic peptide substrate Mca-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2 (also sold as MMP Substrate III), used at 10–20 µM in assay buffer: 50 mM Tris-HCl pH 7.5, 150 mM NaCl, 10 mM CaCl2, 0.05% Brij-35. Recombinant MMP-1 at 1–5 nM final concentration is typically sufficient to generate a linear signal over 30–60 min at 37 °C (excitation ~320 nm, emission ~405 nm). Avoid EDTA or EGTA in the assay buffer — they chelate the catalytic zinc and will abolish activity. Include a no-enzyme blank and a 10 mM EDTA-inhibited control.

What starting concentration of recombinant MMP-1 should I use for collagen degradation or inhibitor IC50 assays?

For fluorogenic peptide-based IC50 determinations, 1–5 nM MMP-1 is a practical starting point; working below the Km of your substrate (~5–20 µM for most Mca-based peptides) keeps the assay in a substrate-excess regime where competitive inhibitor IC50 approximates Ki. For native fibrillar collagen degradation assays (e.g., type I collagen gel contraction or SDS-PAGE collagen cleavage), 10–50 nM enzyme is typically required for visible cleavage within 4–24 h at 37 °C. Titrate enzyme concentration in a preliminary experiment before running inhibitor panels to confirm linearity of signal with respect to enzyme amount.

Does the storage buffer for recombinant MMP-1 interfere with downstream activity assays or cell-based experiments?

The supplied buffer — 50 mM Tris-HCl pH 7.5, 150 mM NaCl, 10% glycerol, 5 mM CaCl2 — is compatible with most biochemical activity assays at typical working dilutions of 1:10 to 1:100. Glycerol at final concentrations below 1% is generally well tolerated. For cell-based experiments, dilute at least 1:20 into serum-free medium to reduce glycerol to ≤0.5% and verify that exogenous CaCl2 at the resulting concentration (~0.25 mM) does not perturb your cell model. Avoid further dilution into EDTA- or EGTA-containing buffers, as these will chelate the calcium required for metalloproteinase stability and activity.

How should I store recombinant MMP-1 and how many freeze-thaw cycles are acceptable?

Store at −20 °C in the single-use aliquots as supplied. Each aliquot is sized to minimize the need for refreezing. Repeated freeze-thaw cycles cause progressive loss of metalloproteinase activity — we recommend no more than two cycles before discarding unused material. For working stocks needed across multiple days, prepare dilutions in assay buffer containing 0.1% BSA and store at 4 °C for up to 48 h. Do not store diluted enzyme at −20 °C without a carrier protein, as adsorption to tube walls at low concentrations will reduce effective activity.

Can I use recombinant MMP-1 as a positive control for Western blot with the matched TPB anti-MMP-1 antibody (RP-MMP1)?

Yes — this is a primary validation use case. Load 20–50 ng of recombinant MMP-1 per lane alongside your cell lysate or conditioned medium samples. The matched rabbit polyclonal antibody RP-MMP1 (see /anti-mmp-1-rabbit-polyclonal-antibody) is raised against MMP-1 and validated for Western blot, so it will detect the recombinant at the expected ~52–57 kDa (proform) or ~44–46 kDa (active form). This pairing is especially useful for confirming antibody performance on new membrane types or blocking conditions, and for setting exposure parameters before running precious biological samples.

How much recombinant MMP-1 should I load as a Western blot positive control, and what band should RP-MMP1 antibody detect?

Load 20–50 ng of recombinant MMP-1 per lane for a clean, non-saturated signal with RP-MMP1 at recommended dilutions (typically 1:500–1:2000 for Western blot — confirm on the RP-MMP1 datasheet). At 20 ng you should see a distinct band at ~52–57 kDa if the proform predominates, or ~44–46 kDa for the fully processed active enzyme. If signal is faint at 20 ng, increase to 50 ng before adjusting antibody concentration. Because both the recombinant and RP-MMP1 originate from the same TPB platform, lot-to-lot compatibility is confirmed — no need to re-validate the pairing when either reagent is re-ordered.