Protein Standards & Ladders - US (2025)

Table of Contents

Protein ladders and standards for SDS-PAGE, western blots, and isoelectric focusing (IEF) On this page: Prestained broad and high molecular weight protein ladders Protein ladders for western blotting and fluorescent western blotting Unstained protein ladders Protein ladders for IEF, native PAGE and specialty applications Ordering information Compare all protein standards and ladders FAQs References

Protein ladders and standards for SDS-PAGE, western blots, and isoelectric focusing (IEF)

Choose from a variety of protein ladders (molecular weight markers) for protein electrophoresis and western blotting applications. Each protein standard or ladder is supplied in a ready-to-use format, eliminating the need to reduce, pre-mix, or add loading dyes. These protein standards and ladders are consistent from lot to lot and are strictly quality controlled on appropriate gels to help ensure consistent band migration and intensity. All prestained protein ladders are compatible for use in western blotting.

Prestained broad and high molecular weight protein ladders

Prestained molecular weight standards are ideal to monitor the progression of the gel electrophoresis run and to estimate protein transfer efficiency. Available in blue and multicolor options, they are compatible with all Invitrogen SDS-PAGE gels. The combination of high molecular weight range protein ladders and NuPAGE Tris-Acetate protein gels is recommended for optimal separation and detection of high molecular weight proteins.

Product description	PageRuler Plus Prestained Protein Ladder Click image to enlarge Request sample	Spectra Multicolor Broad Range Protein Ladder Click image to enlarge	HiMark Prestained Protein Standard Click image to enlarge	SeeBlue Pre-Stained Standard Click image to enlarge
Choose for	Best multicolor prestained ladder for routine applications	4 colors for improved visualization during separation and transfer	Analysis of high molecular weight proteins	Visible monitoring of gel separation and transfer efficiency
Range (kDa)	10–250	10–260	31–460	3–200
Number of bands	9	10	9	9
Recommended gel	All SDS-PAGE gels	All SDS-PAGE gels	NuPAGE Tris-acetate	All SDS-PAGE gels
Recommended Volume per well for 1.0 mm gel (μL)	5 µL for electrophoresis 5 µL for blotting	10 µL for electrophoresis 10 µL for blotting	10 µL for electrophoresis 10 µL for blotting	10 µL for electrophoresis 3 µL for blotting
Visualization method	Colorimetric, NIR fluorescence (700nm channel, blue bands), RGB fluorescence (550 nm channel, orange bands)	Colorimetric, NIR fluorescence (700nm channel, blue bands), RGB fluorescence (550 nm channel, orange bands)	Colorimetric	Colorimetric
Cat. No.	26619 (2 x 250 µL), 26620 (10 x 250 µL)	26634(2 x 250 µL),26623 (10 x 250 µL)	LC5699(250 µL)	LC5625(2 x 250 µL)

Protein ladders for western blotting and fluorescent western blotting

Western blot protein ladders are designed for protein molecular weight estimation directly on the blot during detection. Consisting of recombinant proteins fused to an IgG binding site, these versatile molecular weight ladders bind the primary or secondary antibody used for the detection of the target protein. Western blotting ladders provide a useful positive control to evaluate the performance of the detection antibody. Direct visualization of unstained ladders can also be achieved through standard staining protocols (e.g., Coomassie stains).

Product description	iBright Prestained Protein Ladder Click image to enlarge Request Sample	MagicMark XP Western Protein Standard Click image to enlarge
Choose for	Exceptional versatility for visible, IgG or fluorescent western blot detection	IgG binding for direct visualization during detection of western blot
Range (kDa)	11–250	20–220
Number of bands	12	9
Recommended gel	All SDS-PAGE gels	All SDS-PAGE gels
Recommended volume per well for 1.0 mm gel (μL)	1–3	5–10
Visualization method	Colorimetric, NIR fluorescence (700 nm channel), user defined detection system (2 bands)	User defined detection system (not recommended for RGB fluorescence systems)
Properties	IgG binding sites on 2 bands (80 and 30 kDa), 10 fluorescent, blue-stained bands	IgG binding sites on all bands
Cat. No.	LC5615(2 x 250 µL)	LC5602(250 µL) LC5603(50 µL)

Unstained protein ladders

Unstained protein ladders are useful when performing precise molecular weight determination of the target protein. Unstained protein standards are not labeled with dyes that can alter the apparent molecular weight of the ladder in the gel. They can be visualized by direct staining with Coomassie or other protein stains. PageRuler Unstained Protein Standards contain Strep-tag^TMII sequence and can be immunodetected on the western blot.

Product description	PageRuler Unstained Protein Ladder Click image to enlarge	PageRuler Unstained Broad Range Protein Ladder Click image to enlarge	HiMark Unstained Protein Standard Click image to enlarge
Choose for	14 bands for superior accuracy	Accurate estimation across a broader range	Analysis of high molecular weight proteins
Range (kDa)	10–200	5–250	40–500
Number of Bands	14	11	9
Recommended gel	All SDS-PAGE gels	All SDS-PAGE gels	NuPAGE Tris- Acetate
Recommended Volume per well for 1.0 mm gel (μL)	5	5	5
Visualization method	stain of choice	stain of choice	stain of choice
Properties	Tagged—proteins contain an integral Strep-tag™ II sequence and can be detected on western blots using Strep-Tactin™ conjugates or an antibody against Strep-tag™ II sequence	Tagged— proteins in the 10 -250 kDa range contain a Strep-tag™ II sequence and can be detected on western blots using Strep-Tactin™ conjugates or an antibody against Strep-tag™ II sequence	Direct visualization can be achieved through standard staining protocols (e.g., Coomassie, etc.)
Cat. No.	26614(2 x 250 µL)	26630(2 x 250 µL)	LC5688(250 µL)

Protein ladders for IEF, native PAGE and specialty applications

A selection of protein ladders engineered to provide a reliable reference for protein size determination in native PAGE, pI calibration, detection of His-Tagged, phosphorylated, or glycosylated proteins.

IEF Marker 3-10 Click image to enlarge	NativeMark Unstained Protein Standard Click image to enlarge	E-PAGE SeeBlue Pre-stained Standard Click image to enlarge	BenchMark His-tagged Protein Standard Click image to enlarge	Peppermint Stick Phosphoprotein Molecular Weight Standards Click image to enlarge	CandyCane Glycoprotein Molecular Weight Standards Click image to enlarge
No. of bands
13	8	5	10	6	8
Band weights
~10.7, 9.5, 8.3, 8.0, 7.8, 7.4, 6.9, 6.0, 5.3, 5.2, 4.5, 4.2, 3.5	~1236, 1048, 720, 480, 242, 146, 66, 20 kDa	~261, 173, 97, 42, 21 kDa	~160, 120, 80, 60, 50, 40, 30, 20, 15, 10 kDa	~116, 66, 45, 23.6, 18, 14.4 kDa	~180, 97, 82, 66, 42, 29, 18, 14 kDa
Colors
Unstained	Unstained	Blue, orange, pink	Unstained	Unstained	Unstained
Visualization
Colorimetric	Colorimetric	Colorimetric	Each protein standard contains a 6X His-tag enabling the detection with the InVision His-tag In-gel Stain	Colorimetric or methods that detect phosphorylated proteins such as Pro-Q Diamond phosphoprotein gel stains	Colorimetric or methods that detect glycosylated proteins such as Pro-Q Glycoprotein stain kits
Recommended gel
IEF gels	Native-page gels	E-PAGE gels	All SDS-PAGE gels	All SDS-PAGE gels	All SDS-PAGE gels
Recommended volume per well for 1.0 mm mini gel
5 μL	5 μL	10 μL for electrophoresis, 5 μL for blotting	5 μL for electrophoresis, 2.5–5 μL for blotting	1 μL	0.5 μL
Cat. No.
3921201 (500 µL)	LC0725 (5 x 50 µL)	LC5700 (500 µL)	LC5606 (125 µL)	P33350 (400 µL) P27167 (40 µL)	C21852 (400 µL)

Ordering information

Prestained protein ladders

Western blot and fluorescent protein ladders

Unstained protein ladders

IEF and specialty protein ladders

Compare all protein standards and ladders

Prestained Protein Ladders
	Range kDa	No. of Bands	Recommended gel	Visible	Fluorescence		Western detection
	Range kDa	No. of Bands	Recommended gel	Visible	NIR	RGB	Western detection
PageRuler Plus Prestained Protein Ladder	10–250	9	all SDS-PAGE gels	Blue, Orange, Green
PageRuler Prestained Protein Ladder	10–180	10	all SDS-PAGE gels	Blue, Orange, Green
Spectra Multicolor Broad Range Protein Ladder	10–260	10	all SDS-PAGE gels	Blue, Orange, Green, Pink
SeeBlue Plus2 Pre-stained Protein Standard	3–200	10	all SDS-PAGE gels	Blue, Pink, Orange
Novex Sharp Pre-Stained Protein Standard	3.5–260	12	all SDS-PAGE gels	Blue, Pink, Orange
BenchMark Pre-stained Protein Ladder	6–180	10	all SDS-PAGE gels	Blue, Pink
HiMark Pre-stained Protein Standard	30–460	9	NuPAGE Tris-Acetate	Blue, Pink
Spectra Multicolor High Range Protein Ladder	40–300	8	NuPAGE Tris-Acetate	Blue, Orange, Green
Spectra Multicolor Low Range Protein Ladder	1.7–40	6	Novex Tricine	Blue, Orange, Green
SeeBlue Pre-Stained Standard	3–200	9	all SDS-PAGE gels	Blue
iBright Prestained Protein Ladder	11–250	12	all SDS-PAGE gels	Blue			IgG binding sites
PageRuler Prestained NIR Protein Ladder	11–250	10	all SDS-PAGE gels	Blue
Unstained Protein Ladders
MagicMark XP Western Protein Standard	20–220	9	all SDS-PAGE gels	stain of choice			IgG binding sites
PageRuler Unstained Protein Ladder	10–200	14	all SDS-PAGE gels	stain of choice			Strep-tag™ II sequence
PageRuler Unstained Broad Range Protein Ladder	5–250	11	all SDS-PAGE gels	stain of choice			Strep-tag™ II sequence
PageRuler Unstained High Range Protein Ladder	60–250	8	NuPAGE Tris-Acetate	stain of choice			Strep-tag™ II sequence
Mark12 Unstained Standard	2.5–200	12	all SDS-PAGE gels	stain of choice
BenchMark Protein Ladder	10–220	15	all SDS-PAGE gels	stain of choice
BenchMark Fluorescent Protein Standard	11–155	7	all SDS-PAGE gels	stain of choice
Novex Sharp Unstained Protein Standard	3.5–260	12	all SDS-PAGE gels	stain of choice
SuperSignal Molecular Weight Protein Ladder	20–150	8	all SDS-PAGE gels	stain of choice			IgG binding sites
SuperSignal Enhanced Molecular Weight Protein Ladder	20–150	8	all SDS-PAGE gels	stain of choice			IgG binding sites
Pierce Unstained Protein MW Marker	14–116	7	all SDS-PAGE gels	stain of choice
HiMark Unstained Protein Standard	40–500	9	NuPAGE Tris-Acetate	stain of choice
PageRuler Unstained Low Range Protein Ladder	3.4–100	8	Novex Tricine	stain of choice			Strep-tag™ II sequence

Resources

Download: Protein Gel Guide

Download: Protein gel electrophoresis technical handbook

Download: Western Detection Workflow brochure

Access:

FAQs

What is a protein standard 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.

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What are protein standards? ›

Protein standards are mixtures of well-characterized natural or recombinant proteins that are loaded alongside protein samples in a gel. They are used to help monitor electrophoretic separation as well as estimate the size and concentration of the proteins separated in a gel.

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How much protein ladder to load? ›

Transfer the desired amount of the Prestained Protein Ladder to a separate tube. For blotting: use 5 µl for mini-gels and 10 µl for full length gels. For visualizing during electrophoresis: use 10-15 µl for mini-gels and 20-30 µl for full length gels.

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What is the significance of using a protein ladder in a SDS-PAGE? ›

Staining and Destaining Buffer: The gel is stained with Coomassie Stain Solution. The gel is then destained with the destaining solution. Protein bands are then visible under naked eyes. Protein Ladder: A reference protein ladder is used to determine the location of the protein of interest, based on the molecular size.

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How many different proteins are in the protein ladder? ›

The PageRuler™ Unstained Broad RangeProtein Ladder is a mixture of eleven recombinant, highly purified proteins ranging from 5 kDa to 250 kDa. For easy reference, the 100 kDa, 50 kDa and 20 kDa protein bands have greater intensity than the other proteins in the ladder.

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Do you boil a protein ladder? ›

Thaw the ladder at room temperature. Do not boil protein ladder.

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What is the maximum load that should be carried up a ladder? ›

This is because as a general rule, ladders aren't the right kind of access equipment for routinely heavy or strenuous work. According to law, you also shouldn't carry more than 10kg up a ladder if it's not been subject to a detailed manual handling assessment.

How much ladder to load in SDS-PAGE gel? ›

Load the following volumes of the ladder on an SDS-polyacrylamide gel: – 5 μL per well for mini gel, – 10 μL per well for large gel. Use the same volumes for Western blotting. The loading volumes listed above are recommended for gels with a thickness of 0.75-1.0 mm.

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What is the low range of 10 colored protein ladder? ›

The Low Range OG 10 Colored Protein Ladder is a three-color protein standard with 10 pre-stained proteins covering a wide range of molecular weights for 10 to 180 kDa.

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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.

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What is the purpose of including a standard ladder on the gel? ›

The ladder serves as a reference point by which to judge the size of other protein/ DNA bands on the gel. You can use this and a semi-log plot to determine the rate at which the protein/DNA fragments run. You can then use the equation for the line generated to estimate the size of your sample bands the gel.

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How are protein ladders made? ›

Protein ladders are composed of a series of bands, which are highly purified polypeptides of different well-defined sizes. These polypeptides get resolved during electrophoresis as separate bands - based on their molecular weights.

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What is a standard ladder in gel electrophoresis? ›

Introduction. A DNA ladder is a solution of DNA molecules of different lengths used in agarose or acrylamide gel electrophoresis. It is applied as a reference to estimate the size of unknown DNA molecules that were separated based on their mobility in an electrical field through the gel.