How to Choose a Proteinase Antibody
A structured buying guide for proteinase research: what to check before ordering, how to compare closely-related targets, and links to family-specific selection guides, validation protocols, and research context.
The seven questions to answer before ordering
Choosing a proteinase antibody is different from choosing an antibody to a stable folded protein — proteinases have zymogen, active, and cleaved forms; often multiple family members with 70–95% sequence identity; and application-specific epitope accessibility issues. Work through these questions before adding to cart:
- Which form do I need to detect? Zymogen (proform), active (mature), or cleaved fragments? Many antibodies detect only one form — check the immunogen sequence on the datasheet.
- Which family members must I distinguish? If you need to tell MMP-9 from MMP-2, or Cathepsin B from Cathepsin L, an antibody with cross-reactivity to close relatives will confound your data. Read the cross-reactivity detection guide.
- Which application? Western blot antibodies aren’t interchangeable with IHC or IF antibodies — the epitope may be hidden by fixation or membrane binding.
- Which species? Reactivity is confirmed only for the species listed on the datasheet. Human-only antibodies fail on mouse tissue if the epitope isn’t conserved.
- Monoclonal or polyclonal? See the polyclonal vs monoclonal decision guide and the proteinase-specific version.
- Do I need a matched positive control? If yes, order the recombinant protein for the same target — see recombinant proteins as positive controls.
- Do I need a knockout control? The gold-standard validation. See the CRISPR knockout protocol.
Compare specific antibodies within a family
Detailed side-by-side comparisons for the most commonly-confused proteinase pairs. Each guide covers epitope location, cross-reactivity, isoform selectivity, and application recommendations.
Matrix metalloproteinases (MMP) & ADAMs
Aspartic proteinases
Cysteine proteinases
Serine proteinases
Application-specific protocols
Family-optimized protocols for the standard immunoassays. Buffer choices, transfer times, and dilution ranges differ by target family:
Optimize your western blot before you start
The most common reasons for a “bad antibody” are actually dilution, incubation, or blocking-buffer choices:
When things don’t work
Structured troubleshooting for the two most common signal-quality problems:
Research context
Understanding the biology behind the target you’re assaying helps you pick the right form (zymogen vs active) and the right sample type: