Protein Ladders and Standards (Markers) (2024)

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Protein Ladders and Standards (Markers) (1)

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Prestained Protein Ladders Unstained Protein Ladders Western Blotting Protein Standards IEF and 2D Electrophoresis Protein Standards Resources

Pick the Best Standards for Your Blots!

Just click on the light source in our interactive guide and see how banding pattern changes with light source. This interactive guide helps you pick the best protein standard for your gels and blots.

Try Our Interactive Selection Guide

Featured ProductPrecision Plus Protein Dual Color Standards

  • Brighter for easier target protein identification
  • Stronger band intensity after blot processing
  • Sharper for more accurate MW estimation

Prestained Protein Ladders

Precision Plus Protein Standards have the same gel migration patterns, with three high-intensity reference bands (25, 50, and 75 kD), and provide exceptional lot-to-lot molecular weight consistency.

Dual Color Standards

Kaleidoscope Standards

Dual Xtra Standards

All Blue Standards
Bands 10 10 12 10
Colors 2 5 2 1
MW range 10–250 kD 10–250 kD 2–250 kD 10–250 kD
Band sharpness High High High High
Packaging options Sample (5 applications) 1610374S
50 applications 1610374 1610375 1610377 1610373
250 applications 1610394 1610395 1610397 1610393

Prestained Natural Protein Standards

Prestained natural protein standards for SDS-PAGE and western blotting provide a quick and easy way to monitor protein separation during electrophoresis and to assess transfer efficiency on blots. Each lot of prestained protein standards is individually calibrated for estimating the MW of sample proteins.

Protein Ladders and Standards (Markers) (8)

Important information

Prestained Natural Protein Standards will soon be phased out. We recommend the Precision Plus Protein Prestained Recombinant Protein Standards above as replacements.

Unstained Protein Ladders

Unstained natural protein standards allow accurate MW determination with uniform band intensities on SDS-PAGE gels stained with Coomassie Blue or zinc. Precision Plus Protein Unstained Recombinant Protein Standards are Strep-tagged, enabling immunodetection and molecular weight determination on western blots.

Precision Plus
Protein Unstained



Natural High-Range

Natural Polypeptide
Bands 10 9 6 5 6
MW range
(Note: Actual weights may vary; lot-specific MWs are included with each vial.)
10–250 kD 6.5–210 kD 14–97 kD 45–200 kD 1.4–26.6 kD
Band sharpness High Low Low Low Low
Packaging options 100 applications 1610363 1610317 1610304 1610303 1610326
500 applications 1610396

* Recommended for use with Bio-Rad's TGX Stain-Free Precast Gels and TGX Stain-Free FastCast Acrylamide handcast gels.

Western Blotting Protein Standards

Western blotting protein standards can be used for both fluorescent visualization and colormetric or chemiluminescent immunodetection on western blots. Precision Plus Protein WesternC Standards are combination protein standards containing ten prestained, Strep-tagged recombinant proteins, enabling both fluorescent visualization on gels and colorimetric or chemiluminescent western blot detection with StrepTactin-AP or StrepTactin-HRP Conjugate.

Protein Ladders and Standards (Markers) (14)
Bands 10
Colors 2
MW range 10–250 kD
Band sharpness High
Packaging options 50 applications Standards only (1610376)
Standards and StrepTactin-HRP Conjugate (1610385)
250 applications Standards only (1610399)
Standards and StrepTactin-HRP Conjugate (1610398)

IEF and 2D Electrophoresis Protein Standards

IEF and 2D protein standards are a mixture of native proteins with isoelectric points (pI) ranging from 4.45 to 9.6, providing reproducible pI calibration in native PAGE or agarose IEF gels. 2-D SDS-PAGE protein standards provide calibrated references for protein pI and molecular weight in the second dimension.

Precision Plus Protein
Prestained Plug Standards


Isoelectric Focusing
(IEF) Standards
Bands 10 7 9
Colors 1 1
MW range/pI range 10–250 kD 17.5–76 kD, pI 4.5–8.5 pI 4.45–9.6
24 applications 1610378
Number of applications depends
on staining method
1610320 1610310

* 2-D standards: use 2.5 µl per mini gel for Coomassie staining (200 applications) or 0.5–2.5 µl for silver staining (up to 1,000 applications); use 1.0–5.0 µl for full-length gels (16–20 cm) to yield 100 or up to 500 applications, respectively.
IEF standards: use 5 µl per mini gel for Coomassie staining or 0.5 µl for silver staining to yield 50 or 500 applications, respectively.


Introducing the Western Blot Learning Center

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  • Protein Standards Selection Guide
    (PDF 291 KB)

    For quick guidance on choosing the best standard for your application.

  • Little Book of Standards
    (PDF 5.12 MB)

    Complete reference information for all of Bio-Rad’s protein standards and nucleic acid standards.

  • Protein Gel Migration Charts

    View banding patterns for Bio-Rad protein standards on Bio-Rad and competitor gels.

  • Free Protein Standards Selection Magnet

    Place this handy selection guide magnet on your refrigerator or lab bench to eliminate the guesswork and make protein standard selection simple.
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Protein Ladders and Standards (Markers) (22)

  • Electrophoresis Guide
    (PDF 8.35 MB)

    Theory and techniques, Bio-Rad products, tips and troubleshooting.

  • Protein Blotting Guide
    (PDF 7.11 MB)

    Details on blotting technology, available products, and tips and techniques.

Protein Ladders and Standards (Markers) (2024)


What is a protein ladder or marker? ›

Protein molecular weight markers, sometimes referred to as protein standards or protein ladders, are used to estimate the molecular weight of proteins of interest and to monitor the progress of electrophoretic separation or transfer in Western blotting.

What are the common protein ladders? ›

Compare all protein standards and ladders
Prestained Protein Ladders
BenchMark Pre-stained Protein Ladder6–180all SDS-PAGE gels
HiMark Pre-stained Protein Standard30–460NuPAGE Tris-Acetate
Spectra Multicolor High Range Protein Ladder40–300NuPAGE Tris-Acetate
Spectra Multicolor Low Range Protein Ladder1.7–40Novex Tricine
24 more rows

What is the protein ladder in SDS? ›

Fluorescent protein ladders are used in SDS-PAGE gels or polyacrylamide gel electrophoresis (involving tris-glycine buffer). They contain a mixture of proteins that are pre-stained with fluorescent dyes. The bands fluoresce when the light of a specific wavelength falls on them.

What is the protein marker high range? ›

Color-coded Prestained Protein Marker, High Range (43-315 kDa) is a mixture of purified proteins, covalently coupled to blue, green, orange, or pink dyes, that resolves to 8 bands between 43 and 315 kDa when electrophoresed. The protein concentrations are carefully balanced for even intensity.

What is the difference between marker and ladder? ›

DNA marker means a sequence of DNA used to mark a particular location on a particular chromosome while DNA ladder is just DNA fragment of specific size and it could be from any source of DNA .

What is the purpose of the ladder or marker? ›

A molecular-weight size marker, also referred to as a protein ladder, DNA ladder, or RNA ladder, is a set of standards that are used to identify the approximate size of a molecule run on a gel during electrophoresis, using the principle that molecular weight is inversely proportional to migration rate through a gel ...

What is a standard molecular ladder? ›

Molecular weight markers, or ladders, are a set of standards that are used for determining the approximate size of a protein or a nucleic acid fragment run on an electrophoresis gel. These standards contain pre-determined fragment (or protein) sizes and concentrations.

Why do we need a protein ladder? ›

Protein ladders, also known as protein markers or protein standards, are used to help estimate the size of proteins separated during electrophoresis. They serve as points of reference because they contain mixtures of highly purified proteins with known molecular weights and characteristics.

Why use an unstained protein ladder? ›

Unstained protein ladders are more accurate for sizing proteins, as the dyes used in prestained ladders can slightly distort the apparent size of the protein ladder proteins on the gel.

What is the protein standard for SDS? ›

Unstained Natural Protein Standards for SDS-PAGE are blended to give uniform band intensities when stained with Coomassie Blue R-250 or zinc stains. Natural SDS-PAGE Standards are available in broad, low, high, and polypeptide molecular weight ranges, allowing calibration in almost any percentage gel.

How to use a protein ladder? ›

Preparing and Loading Protein Ladders (P7711)
  1. Thaw the ColorPlus Prestained Protein Ladder at room temperature. ...
  2. Transfer the desired amount of the Prestained Protein Ladder to a separate tube. ...
  3. Heat the ColorPlus Prestained Protein Ladder at 95-100°C for 3-5 minutes. ...
  4. Load directly onto SDS-PAGE gel and electrophorese.

What is a standard ladder in gel electrophoresis? ›

A DNA ladder is a solution composed of DNA molecules of varying lengths. It is widely used in gel electrophoresis as a reference point or molecular-weight size marker to determine the approximate size of unknown DNA fragments.

What are the protein markers? ›

Protein molecular weight markers, sometimes referred to as protein standards or protein ladders, are used to estimate the molecular weight of proteins of interest and to monitor the progress of electrophoretic separation or transfer in Western blotting.

What number is considered high protein? ›

People who exercise regularly also have higher needs, about 1.1–1.5 grams per kilogram. People who regularly lift weights, or are training for a running or cycling event need 1.2–1.7 grams per kilogram. Excessive protein intake would be more than 2 grams per kilogram of body weight each day.

What should a normal protein level be? ›

The normal range is 6.0 to 8.3 grams per deciliter (g/dL) or 60 to 83 g/L. Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results. The examples above show the common measurements for results for these tests.

What is a marker protein? ›

Marker proteins extend across the cell membrane and serve to identify the cell. The immune system uses these proteins to tell friendly cells from foreign invaders. They are as unique as fingerprints. They play an important role in organ transplants.

What is a protein marker in a cell? ›

Ribosomes: they are the organelle that 'manufactures' proteins in a process called translation or protein synthesis. In eukaryotic cells, ribosomes can be free in the cytoplasm, or they can be bound to the outer surface of the membrane of either the rough endoplasmic reticulum or the nuclear envelope.

Why are protein ladders used? ›

Protein ladders or molecular weight markers are among the most commonly used reagents in biochemistry experiments. They provide molecular weight standards to estimate the size of proteins separated by gel electrophoresis like SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis).


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