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PageRuler Unstained Protein Ladder

Unstained MW marker composed of 14 recombinant proteins.

PageRuler Unstained Protein Ladder (Molecular Weight Marker)

Thermo Scientific PageRuler Unstained Protein Ladder is a mixture of 14 recombinant, highly purified, unstained proteins (10kDa to 200kDa) for use as size standards in protein electrophoresis (SDS-PAGE) and Western blotting.

Each protein in the ladder contains an integral Strep-tag™ II Sequence which can be detected directly on Western blots using a Strep-Tactin™ Conjugates or an antibody against Strep-tag™ II Sequence (see Refs 2-3). The Ladder produces sharp bands on SDS-polyacrylamide gel following staining of the gel with Thermo Scientific Pierce Gel Stains or other coomassie dye or silver stains. The 50kDa protein band is of greater intensity and serves as a reference band.


  • Size range – 14 proteins spanning 10 to 200kDa
  • Ready-to-use – supplied in a loading buffer for direct loading on gels
  • Sharp bands – excellent accuracy for detection in with coomassie or silver stains
  • Reference band – 50kDa band is has greater intensity for easy orientation
  • Tagged – each protein in the ladder contains an integral Strep-tag™ II Sequence
  • Quality tested – each lot evaluated by SDS-PAGE and Western blotting


  • Proteins (0.02 to 0.05mg/mL of each) in 62.5mM Tris-H3PO4 (pH 7.5 at 25°C), 1mM EDTA, 2% SDS, 10mM DTT, 1mM NaN3, 0.01% bromophenol blue and 33% glycerol


  • Accurate protein sizing on SDS-polyacrylamide gels and Western blots.

Product Details:

SDS-PAGE band profile of the Thermo Scientific PageRuler Unstained Protein Ladder.
SDS-PAGE band profile of the Thermo Scientific PageRuler Unstained Protein Ladder. Images represent 8-16% Tris-glycine gels (SDS-PAGE). Gel was stained with coomassie blue dye; blot was detected with a Strep-Tactin™-AP Conjugate and NBT/BCIP substrate.


  1. Laemmli, U.K. (1970). Cleavage of structural proteins during the assembly of the head of bacteriophage T4, Nature, 227, 680-685.
  2. Schmidt, T.G.M., Skerra, A. (1993). The random peptide library-assisted engineering of a C-terminal affinity peptide, useful for the detection and purification of a functional Ig Fv fragment, Prot. Engineering, 6, 109-122.
  3. Tsiotis, G., et al. (1995). Isolation and structural characterization of trimeric cyanobacterial photosystem I complex with the help of recombinant antibody fragments, Eur. J. Biochem., 231, 823-830.

Related Resources:

Protein Molecular Weight Markers – product comparison and selection guide
Protein Gel Stains and Kits – compare colorimetric and fluorescent gel stains

Related Products:

Precise Protein Gels – browse all pre-cast gels for SDS-PAGE
BupH Dry Blend Electrophoresis Buffers – Tris-HEPES-SDS and other pouched electrophoresis buffers
Reducing Agents – 2-mercaptoethanol, DTT, TCEP and other reducing agents
Western blotting substrates and reagents – find kits, stripping buffers, blotting membranes and film

Ordering Information
Product # Description Pkg. Size Instructions MSDS CofA Price
26614 PageRuler Unstained Protein Ladder
Formulation: 14 proteins from 10 to 200kDa in reducing sample buffer
Sufficient For: 50 to 100 mini gel lanes at 5 to 10µL per lane
2 x 250┬ÁL Product Instructions for product #26614 PageRuler Unstained Protein Ladder MSDS for product #26614 PageRuler Unstained Protein Ladder Certificate of Analysis for product #26614 PageRuler Unstained Protein Ladder $89.00

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Instructions | MSDS | CofA
Product Instructions | MSDS | CofA  

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