Detergents - also termed as tensides or surfactants - are amphipathic compounds with both lipophilic (hydrophobic; non-polar) and hydrophilic (polar) sites within one molecule. Therefore they are soluble in aqueous solution as well as in non-polar organic solvents - and they are able to influence the solubility of other molecules (like lipids or hydrophobic proteins in buffer solutions). Detergents are widely used in biochemistry, cell biology or molecular biology. Cell lysis, protein solubilization, protein crystallization or reduction of background staining in blotting experiments are just a few examples.

Detergents can be classified for instance according to their chemical structure stating their constituent polar and nonpolar group (glucosides, alkyl ionic detergents, polyoxyethylene alcohols, bile salts, sulphonates etc.), the charge character (anionic, cationic, zwitterionic = amphoteric; non-ionic) or simply whether they are mild or strong in terms of their ability to solubilize and / or to denature proteins. We decided to arrange our detergents according to their charge:

anionic detergents

cationic detergents

zwitterionic detergents

non-ionic detergents

isomeric pure detergents for crystallography

But how to choose the right detergent?  Selectionguide

There is a large number of different detergents available and choosing the best detergent for a special application is not trivial. In many cases, a set of detergents has to be tested to select the one with the best properties. If the goal is the isolation of a protein preserving its structural and functional state, one should consider the temperature, the pH and the ionic strength of the system as well as interference with assays. Several other parameters may influence the choice too. Assuming that the factors mentioned above are dictated by the protein and are held constant, the factors that are left to be optimised are the detergent's strength (in this case a mild, non-denaturating one), chemical structure, solubility and concentration.

Above a critical concentration, called CMC value (Critical Micellar Concentration), detergents start forming stable aggregates (micelles). The CMC value is specific to each detergent and different factors (chemical structure, pH value, temperature, ionic strenth) may influence it. In aqueous solutions, the hydrophilic site of the monomers will be on the outside of the micelle, and the lipohilic portion inside. In organic solvents, reversed micelles form, with the lipophilic site outside. The micelle size increases and the CMC decreases with increasing size of the lipophilic part of the detergent and, to a lesser extent, with decreasing size and polarity of the polar groups. That means, that detergents with a higher hydrophilic part are characterized by a higher CMC (start to form micelles at higher concentrations) and smaller micelles than higly lipophilic detergent. Above the CMC, free monomer molecules are in equilibrium with the micelles and the solubilizing ability increases. Detergents with high CMC values are more easily removed by dialysis.

More detailed informationen about detergents is provided in our broschure "Detergents"; including criteria for selection, hints for isolation, solubilisation and reconstitution of membrane proteins, references and more.

Overview Detergents

anionic detergents
Prod. No.
Description M [g/mol]
CMC (25°C) Comment                                                                             
A1018

1-Decanesulfonic acid sodium salt

244.33   For IPC (ion pair chromatography); suitable for analysis of amino acids and peptides by HPLC: ion pair reagents influence the retension time of amino acids on HPLC columns.
A1019

1-Dodecanesulfonic acid sodium salt

272.38 9.8 mM See A1018
A3708

1-Heptanesulfonic acid sodium salt anhydrous

202.25   See A1018. This product is also available as monohydrate: A1015
A3729

1-Hexanesulfonic acid sodium salt anhydrous

188.22   See A1018. This product is also available as monohydrate: A1014
A1017

1-Nonanesulfonic acid sodium salt

230.30   See A1018.
A1016

1-Octanesulfonic acid sodium salt

216.28   See A1018.
A1709

1-Pentanesulfonic acid sodium salt anhydrous

174.20   See A1018. This product is also available as monohydrate: A1013

A7402

N-Lauroylsarcosine sodium salt

293.39 13.7 mM

High solubility in chaotrope high salt solutions (in contrast to SDS) and therefore first choice for applications in guanidinium-containing lysis buffers: Addition to cell or tissue homogenates improves the purity of RNA isolated by the guanidine hydrochloride method.

Laurylsarcosine releases chromatin from all proteins and increases the activity of RNA polymerase II (probably by improved access of the polymerase to the template).
We also provide laurylsarcosinate solutions and different qualities, e.g. ultrapure A1163 

A1385

Lithiumdodecylsulfat (LiDS)

272.33 8.7 mM Higher solubility than SDS. The LiDS-PAGE (Polyacrylamide gel electrophoresis with LiDS) is performed at 4°C providing an improved separation.
A0979

Sodium cholate

430.57 10 mM

Water soluble bile salt; component of different lysis buffers (e.g. RIPA). Further applications are liposome preparations, isolation of membrane proteins or lipids, affinity chromatography and cell culture. Sodium cholate should not be used for ion-pairing exchange chromatography or electrophoresis, and when working with enzymes, that need bivalent cations for their activity. It does not interfere with protein assays and can easily be dialysed.

A1531

Sodium deoxycholate

414.57 2.7 mM (20°C) See A0979
A2572

SDS (sodium dodecylsulfate)

288.38 8.2 mM The main field of application is polyacrylamide electrophoresis; SDS binds almost all water soluble proteins (~1,4 g SDS / g protein) and enables protein separation by size (without considering the native charge or tertiary structure). Further application is in blotting and cell lysis. We offer SDS in different qualities and as solution (20- or 10%SDS, A0676).

 

cationic detergents
Prod. No.
Description M [g/mol]
CMC (25°C) Comment                                                                
A6834

Benzethonium chloride

448,08   Quaternary ammonium salt with antimicrobial activity; it is used as a preservative and disinfectant in cosmetics, dairies and food industries. Reagent for the determination of total protein in urine and cerebrospinal fluid (CSF). Protease inhibitor. Readily soluble in water. Incompatible with anionic detergents.
A0742

Cetylpyridinium chloride monohydrat

358.01 0.12 mM Quaternary ammonium salt; antiseptic.
A0805

Cetyltrimethylammonium bromide (CTAB)

364.46 0.92 mM Used in polyacrylamide gel electrophoresis for proteins, which show an unusual migration behavior in the SDS-PAGE (e. g. strongly charged proteins or subunits of membrane proteins).
Another important application of CTAB is the precipitation of high molecular weight DNA, especially from plant material. For this application we suggest to use CTAB molecular biologie grade, A6284
A4147

Dodecyltrimethylammonium bromide (DTAB)

308.35 15 mM  

 

zwitterionic detergents
Prod. No.
Description M [g/mol]
CMC (25°C) Comment                                                                
A1099

CHAPS

          

614.89 6.5 mM Cholate derivative; suitable for experiments that require functional proteins in their native state. No interference with protein assays according to Lowry. Easy to remove by dialysis.
A1100

CHAPSO

       

630.87 8 mM Similar to CHAPS; suitable for solubilisation while retaining proteine activity.
A1460

Sulfobetaine SB 12

335.55 3.3 mM Membrane proteins are better solubilized from membranes than with Nonidet® P40 or Triton® X-100. Proteins are not getting denaturated. 
A1162

Sulfobetaine SB 14

363.60 0.3 mM Might be more efficient in several applications than SB 12. Longer alkyl chains do not improve the impact of this class of detergents.

 

non-ionic detergents
Prod. No.
Description M [g/mol]
CMC (25°C) Comment                                                                
A1381

Brij® 35

1198.56 0.09 mM Mild detergent with a polyoxyethylen head group. As a rule, these detergents do not denature proteins, making them a useful tool in studying proteins in their native state. Proteins, that are composed of several subunits will not dissociate.

This product is also available as a 10% solution (peroxide-free): A1286

A1669

Brij® 58

1123.51 0.077 mM Incubation of living cells with this detergent produces the so-called cytoskeleton. Proteins leak from the cells after a lag phase, depending on the detergent concentration, time of exposure and cell type. Enzyme activity may be determined in the presence of Brij® 58.

This product is also available as a 10% solution (peroxide-free): A2495

A1698

Deoxy-BIGCHAP

862.07 1.1 - 1.4 mM Mild detergent; completely soluble at 0°C. Suitable for the extraction of the opiate receptor in its active state from membranes  Good alternative to CHAPS, CHAPSO and octylglucoside; due to its reduced electrostatic properties it does not disturb anion exchange chromatography (DEAE cellulose).
A1905

Digitonin

1229.34   Steroid glycoside from Digitalis purpurea; permeabilize plasma membranes (this capability may differ from batch to batch from all suppliers!) and form complexes with cholesterol. Frequently used to dissolve membrane-bound proteins. Digitonin is hardly soluble in either water, chloroform or ether. You may dissolve it in absolute ethanol or DMSO. 
A1384

HECAMEG

335.39 19.5 mM Mild, non-denaturing detergent with a high water-solubility. Its high CMC allows the easy removal by dialysis. Does not interfere with protein determination according to Lowry.
A1386

MEGA-8

321.42 58 mM

N-D-Gluco-N-methylalkanamide; chemical analoga of alkyl glucoside. Easily removable by dialysis. No absorbance at 280 nm (in contrast to NP40 and Triton® X-100). Compatible with ion pair chromatography and numerous buffers. During solubilisation of membranes, the embedded proteins are not denaturated, but protein-protein-interactions are released.

Purity > 99 %; free of alpha-isomer.

A3893

MEGA-9

335.44 25 mM

N-D-Gluco-N-methylalkanamide, see MEGA-8.

Purity > 99 %; free of alpha-isomer.

A4761

MEGA-10

349.47 6-7 mM

N-D-Gluco-N-methylalkanamide, see MEGA-8.

Purity > 99 %; free of alpha-isomer.

A1694 Nonidet® P40 (Substitute) §   0.34 mM

Suitable for isolation of core proteins and cytoplasmatic proteins from eukaryotic cells (RIPA lysis buffer). Affects the protein-DNA bound; caution in electrophoretic mobility shift assays!
Adding NP40 into the sequencing reaction of linear or "supercoiled" plasmid DNA increases the quality and avoids additional alkaline denaturation.

This product is also available as a 10% solution (peroxide-free): A2239

A6824

n-Octyl-D-glucopyranoside

n=7

292.38   Anomeric mixture of n-Octyl-α-D-glucopyranoside and n-Octyl-β-D-glucopyranoside (7:3).
A8992 rac.-1-Oleoyl-glycerol 356.50   Monoolein; Purity > 99 %
A1288 Pluronic® F-68 ˜8350   Copolymers from ethylene- (approx. 80 %) and propylene oxide. Pluronic F-68 is applied in the culturing of mammalian cells in large batches. It prevents the sticking of air bubbles to cells, which develope during mixing within the fermentor, stabilizes the foam on the surface or improves the resistance of the cell membrane against hydrodynamic shearing.
A2225

Sucrose monolaurate

524.60 0.4 mM Mild detergent; very well suited for isolation and reconstitution of the visual pigments (rhodopsin) from membranes. A series of sucrose ester has been tested in the determination of the absorption maximum of visual pigments and sucrose monolaurate has been found to be the optimal detergent. Difficult to remove it by dialysis.
A4518 Saponin from Quillaja Bark    

Mixture of terpenoid molecules and glycosides. Permeabilizes the cell membrane by interaction with the cholesterol present in the cell membrane. Thereby large pores form; enabling the entry of conjugated antibodies. Saponin has become the detergent of choice for cytokine staining and phospho-epitope staining protocols.

A1388

Triton® X-100

646.85 0.3 mM Mild detergent that hardly denatures proteins. Part of many lysis buffers. Difficult to remove it by dialysis. Interferes with protein detection according to Folin and Lowry. Triton® X-100 is also available as a 10% solution (peroxide-free): A1287
A3848

Triton® X-114

558.75 0.35 mM

Triton® X-114 forms a clear, micellar solution at low temperatures. Above 20°C, two phases are formed by aggregation of micells. Extraction of cellular material for the isolation of proteins is performed at low temperatures. 

Triton® X-114 is also available as a 10% solution (peroxide-free): A3849

A1389 Tween® 20 1227.72 0.059 mM

Polysorbat 20; common component in immunoassay-buffers; interferes with protein determination according to Bradford.

Also available in other qualities and as a 10% solution (peroxide-free):

A1284

A1390 Tween® 80 1310 0.01 mM

Polysorbat 80; also available as a 10% solution (peroxide-free): A1285

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Isomeric pure alkyl-β-D-glucosides for isolation und Crystallisation of membrane proteins

            

Prod. No.
Description M [g/mol]
CMC (25°C) Comment                                                                
A3208

n-Decyl-β-D-glucopyranoside

(n=9)

320.43 2.2 mM (20°C) Purity > 99 %; free of alpha-isomer.
A5890

n-Dodecyl-β-D-glucopyranoside

(n=11)

348.48 0.19 mM Purity > 99 %; free of alpha-isomer.
A6807

n-Heptyl-β-D-glucopyranoside

(n=6)

278.35 79 mM Purity > 99 %
A6742

n-Nonyl-β-D-glucopyranoside

(n=8)

306.40 18-20 mM Purity > 99 %; free of alpha-isomer.
A1010

n-Octyl-β-D-glucopyranoside

(n=7)

292.38 25-30 mM

One of the frequently used detergents in membrane research: Non-denaturating (allows isolation of functional proteins); Highly water soluble and easily removable by dialysis. No absorbance at 280 nm.

Purity > 99 %; free of alpha-isomer. Also available in "Crystallography grade" (Purity > 99.5 %): A6813

A1145

n-Octyl-β-D-thioglucopyranoside

308.44 9 mM

Alternative to octylglucoside. More stable in solution than octylglucoside; not cleavable by β-Glucosidases.

Purity > 99 %; free of alpha-isomer.

Isomeric pure alkyl-β-D-maltosides for isolation and Crystallisation of membrane proteins

A6816

n-Decyl-β-D-maltoside

(n=9)

482.57 1.8 mM Purity > 99 %; free of alpha-isomer. Also available in "Crystallography grade" (Purity > 99.5 %): A6769
A0819

n-Dodecyl-β-D-maltoside

(n=11)

510.63 0.15 -0.19 mM

Lauryl maltoside; primarily developed for isolation of the mitochondrial cytochrom c oxidase.

Purity > 99 %; free of alpha-isomer. Also available in "Crystallography grade" (Purity > 99.5 %): A6817

A6821 n-Dodecyl-1-thio-β-D-maltoside     Purity > 99 %
A8999 n-Dodecyl-α-D-maltoside 510.63 ~ 0.15 Purity > 99 %; free of beta-isomer.
A6820

n-Hexyl-β-D-maltoside

(n=5)

426.40   Purity > 99 %
A6814

n-Nonyl-β-D-maltoside

(n=8)

468.41 6 mM Purity > 99 %; free of alpha-isomer. Also available in "Crystallography grade" (Purity > 99.5 %): A6768
A6809

n-Octyl-β-D-maltoside

(n=7)

454.40 23 mM Purity > 99 %
A4810

n-Tetradecyl-β-D-maltoside

(n=13)

538.63   Purity > 99 %
A6771

n-Tridecyl-β-D-maltoside

(n=12)

524.64 0.033 mM For Crystallography; purity > 99.5 %; free of alpha-isomer.
A6808

n-Undecyl-β-D-maltoside

(n=19)

496.59 0.6 mM Purity > 99 %; free of alpha-isomer. Also available in "Crystallography grade" (Purity > 99.5 %): A6770

 

Legend

§ Mixture of 15 homologues

Trademarks:

Brij (Atlas Chemicals Co.)

Nonidet (Shell)

Triton (Union Varbide Co.)

Pluronic, Tween (ICI America Inc.)

Abbreviations

CHAPS (3-(3-Cholamidopropyl)-dimethylammonio-1-propanesulfonate), CHAPSO (3-(3-Cholamidopropyl)-dimethyl-ammonio-2-hydroxy-1-propanesulfonate), Deoxy-BIGCHAP (N,N-Bis-[3-(D-gluconamido)-propyl]-deoxycholamide), HECAMEG (6-O-(N-Heptylcarbamoyl)-methyl-α-D-glucopyranoside), MEGA-8 (Octanoyl-N-methylglucamide), MEGA-9 (N-Nonanoyl-N-methylglucamine), SDS (Sodium dodecylsulfate), Sulfobetaine SB 12 (N-Dodecyl-dimethyl-3-ammonio-1-propanesulfonate), Sulfobetaine SB 14 (N-Tetradecyl-dimethyl-3-ammonio-1-propanesulfonate)

Selectionguide:

General properties of the main classes of detergents

Ionic detergents contain a negatively (anionic detergent) or positively (cationic detergent) charged hydrophilic head group. The hydrophobic part is either an alkyl chain (as for SDS, CTAB or alkyl sulfonic acids) or a more complicated steroidal structure as a bile acid salt (like cholate and deoxycholate). The latters are more rigid in their structure and carry additional hydrophilic groups (hydroxyl groups) within the hydrophobic steroide scaffold. Thus, bile salts only show a polar and an apolar face, not a well-defined polar head group.

The size of the micelles is affected by repulsion forces between the charged polar groups and hydrophobic attraction between the side chains. As a result, the micellar size of ionic detergents can be manipulated by the ion strength. Increasing the concentration of neutralizing counter ions leads to a larger micelle size. At the same time, the increased ion strenth results in a lower CMC. Changing the temperature on the other hand only slightly influences the CMC. Ionic detergents generally have higher CMC values than their non-ionic analoga.

Alkyl-ionic detergents mostly act denaturating and separate protein complexes into their subunits.

Non-ionic detergents possess an uncharged, hydrophilic head groups consisting of either polyoxyethylene units (e.g. Brij® und Triton®) or sugars (alkyl glucosides or maltosides). The CMC value and micellar size of this detergent group is mainly affected by temperature (as higher the temperature as higher the CMC), not by ion strength.

Non-ionic detergents generally are non-denaturating and therefore first choice for applications, that require preservation of protein structure and activity. They are mild detergents that primarily break lipid-lipid and lipid-protein interactions, while protein-protein interactions stay unaffected. Especially alkyl glycosides and maltosides are suitable for isolation of biological active membrane proteins; advantages over polyoxyethylene detergents are e.g. homogenity in composition and structure (many polyoxyethylenes are composed of several homologs) und a lack of absorbance at 280 nm (detergents containing aromatic rings absorb in
the ultraviolet region and may interfere with spectrophotometric monitoring of proteins at 280 nm).

Zwitterionic detergents, like CHAPS or sulfobetaine, combine the features of ionic and non-ionic detergents. Like non-ionic detergents they have no net charge. Consequently they show no electrophoretic mobility and do not bind to ion-exchange resins. Compared to ionic detergents, their CMC values are less sensitive to changes in ion concentration, but they have in common to break protein-protein interactions efficiently (denaturating effect).

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