ubi1 Antibody

What is the Ubi-1 antibody and what epitope does it recognize?

Ubi-1 is a mouse monoclonal antibody specific to ubiquitin that particularly recognizes the human gene UBB (Polyubiquitin-B) . The epitope for this antibody is located in the peptide IQDKEGIPPDQQRLIFAGKQ, corresponding to amino acids 30-49 of bovine Ubiquitin. The central 10 amino acid segment, GIPPDQQRLI, is likely the most significant component of this antibody's epitope . This strategic epitope positioning allows the antibody to interact with ubiquitin in various molecular contexts, though with preferential binding to polyubiquitin chains over monoubiquitinated molecules or free ubiquitin .

What are the validated applications for Ubi-1 antibody in research?

The Ubi-1 antibody has been validated for multiple research applications including:

• Western blot (WB) at dilutions of 1:1,000-1:2,000

• Immunohistochemistry on paraffin-embedded sections (IHC-p)

• Immunofluorescence (IF) at dilutions of approximately 1:2,000

• Immunocytochemistry (ICC)

• Enzyme-linked immunosorbent assay (ELISA)

• Immunoprecipitation (IP)

For optimal results in Western blotting applications, researchers should note that dilution factors may need adjustment based on detection method sensitivity and protein expression levels.

What species reactivity has been confirmed for Ubi-1 antibody?

Ubi-1 antibody demonstrates broad cross-species reactivity, which is consistent with the high conservation of ubiquitin across evolutionary lineages. Confirmed reactivity includes:

• Mammals: Human, Mouse, Rat, Monkey, Horse, Bovine, Porcine

• Birds: Chicken

• Fish: Danio (zebrafish)

• Invertebrates: Drosophila, Caenorhabditis elegans

This extensive cross-reactivity makes Ubi-1 a versatile tool for comparative studies across different model organisms.

How should Ubi-1 antibody be stored to maintain optimal activity?

For maximum preservation of antibody functionality, Ubi-1 antibody should be shipped at 4°C. Upon receipt, researchers should aliquot the antibody to minimize freeze-thaw cycles and store at -20°C for long-term preservation . The antibody is typically supplied in Phosphate Buffered Saline with 50% Glycerol and 5mM Sodium Azide, which helps maintain stability during storage. It is critical to avoid repeated freeze-thaw cycles as these can lead to protein denaturation and subsequent loss of antibody activity and specificity.

What are the recommended Western blot protocols when using Ubi-1 antibody?

For optimal Western blot results with Ubi-1 antibody, researchers should consider the following protocol guidelines:

• Use standard SDS-PAGE separation for protein samples

• Transfer proteins to a membrane using standard protocols

• Block membranes in 5% non-fat milk in TBS-T for approximately 1 hour at room temperature

• Dilute Ubi-1 antibody to 1:1,000-1:2,000 in 5% BSA in TBS-T

• Incubate membranes with diluted primary antibody overnight at 4°C

• Wash membranes with TBS-T (3-5 washes, 5 minutes each)

• Proceed with appropriate secondary antibody incubation and detection

Unlike some other ubiquitin antibodies (such as VU-1), standard membrane preparation is sufficient for Ubi-1, without requiring glutaraldehyde pretreatment of transfer membranes .

How does Ubi-1 antibody compare to other ubiquitin antibodies in terms of specificity and sensitivity?

When compared to other ubiquitin antibodies, Ubi-1 shows distinct binding preferences:

• Ubi-1 recognizes polyubiquitin chains more strongly than monoubiquitinated molecules or free ubiquitin

• It specifically recognizes ubiquitinated cytoplasmic proteins

• In comparative studies with other ubiquitin antibodies (like VU-1, P4d1, 1b4, 6C1, FK1, and FK2), each antibody shows different affinities for various ubiquitin chain types and lengths

The VU-1 antibody has been documented as the "gold standard" for binding all types of poly-ubiquitin chains with high affinity and specificity . Researchers should select the appropriate antibody based on their specific experimental needs and the ubiquitin structures they aim to detect.

How do sample preparation methods affect Ubi-1 antibody detection efficiency?

Sample preparation significantly impacts Ubi-1 antibody detection efficiency. While standard protocols work well with Ubi-1, researchers should consider these factors:

• Preservation of ubiquitinated proteins during lysis by including deubiquitinase inhibitors (like N-ethylmaleimide or PR-619)

• Selection of appropriate lysis buffers that maintain protein conformation while effectively extracting ubiquitinated proteins

• Controlling temperature during extraction to prevent enzymatic degradation

• Optimizing protein loading amounts - typically 30 ng of poly-ubiquitins per lane on SDS-PAGE provides good signal with Ubi-1

Unlike some other ubiquitin antibodies that require special membrane treatments, Ubi-1 works effectively with standard Western blot protocols, making it more convenient for routine applications.

How can Ubi-1 antibody be used to investigate ubiquitin chain linkage types?

Ubi-1 antibody can be used to study different ubiquitin chain linkage types, but researchers should be aware of its binding preferences. Experimental approaches include:

• Comparative analysis using linkage-specific antibodies alongside Ubi-1

• Using recombinant ubiquitin chains of defined linkage types (K48, K63, K11, etc.) as controls

• Employing deubiquitinase treatment controls that selectively cleave specific linkage types

What are common troubleshooting strategies when using Ubi-1 for detecting ubiquitinated proteins?

When troubleshooting Ubi-1 antibody use, researchers should consider:

• High background issues:

  • Increase blocking time or blocking agent concentration

  • Optimize antibody dilution (try more dilute solutions)

  • Include additional wash steps

  • Ensure sample integrity by using fresh protease inhibitors

• Weak or no signal:

  • Verify protein transfer efficiency

  • Check for protein degradation during sample preparation

  • Enrich ubiquitinated proteins prior to analysis

  • Confirm antibody integrity (avoid repeated freeze-thaw cycles)

• Non-specific bands:

  • Include appropriate negative controls

  • Use more stringent washing conditions

  • Validate with alternative ubiquitin detection approaches

How can Ubi-1 antibody be integrated into mass spectrometry-based ubiquitinome studies?

Ubi-1 antibody can enhance mass spectrometry-based ubiquitinome studies through:

• Immunoprecipitation of ubiquitinated proteins prior to mass spectrometry analysis

• Validation of mass spectrometry-identified ubiquitinated proteins using orthogonal Western blot detection

• Enrichment of specific ubiquitinated protein populations before mass spectrometry

• Confirmation of ubiquitination sites identified by mass spectrometry

The specificity of Ubi-1 for ubiquitinated cytoplasmic proteins makes it particularly useful for focusing analysis on this cellular compartment .

What controls should be included when using Ubi-1 antibody in ubiquitination research?

Rigorous experimental design with Ubi-1 should include these controls:

• Positive controls:

  • Recombinant ubiquitin chains of known length and linkage type

  • Cell lysates treated with proteasome inhibitors to accumulate ubiquitinated proteins

• Negative controls:

  • Isotype control antibodies (Mouse IgG1) to identify non-specific binding

  • Samples treated with deubiquitinating enzymes to remove ubiquitin modifications

  • Untreated versus treated samples when studying induced ubiquitination

• Validation controls:

  • Parallel detection with alternative ubiquitin antibodies

  • Ubiquitin knockdown/knockout samples when available

Including the appropriate Mouse IgG1 isotype control (available as clones MOPC-21 or PPV-06) is particularly important for immunoprecipitation experiments to distinguish specific from non-specific binding .