Overview: Detergent Solutions
Detergent Solutions
A detergent is an agent that primarily acts as a surfactant by decreasing the surface tension of a fluid [1]. These are used to manipulate hydrophobic-hydrophilic interactions between biological substances. Detergents play a role in various biological processes and are often delivered as detergent solutions into experimental or manufacturing workflows. These solutions can vary in concentration, and their concentrations are often directly correlated to their strength. Detergent solutions have the flexibility to perform several operational tasks, including the following common practices in biochemistry.
- Cell lysis: Detergents can break down the cell membrane resulting in the lysing of cells to release soluble native and recombinant proteins.
- Solubilization of membrane proteins and lipids: Detergents can form micelles around the hydrophobic parts of membrane proteins and lipids, making them soluble in aqueous solutions.
- Protein crystallization: Detergents can affect the size, shape, and stability of protein crystals by interacting with the protein surface.
- Prevention of non-specific binding: Detergents can reduce the background noise and increase the signal-to-noise ratio in affinity purification and immunoassay procedures by blocking the non-specific binding sites on the solid phase or the target molecule.
- Electrophoresis: Detergents can improve the separation and resolution of proteins in electrophoresis by modifying their charge, shape, and solubility.
By employing a detergent solution into these processes, scientists and researchers can minimize excess variables, background noise, and non-specific binding, resulting in a much more efficient, accurate, and streamlined process. The concentration and composition of detergents holds a direct impact on the experiment in question.
Acid and Base Reaction Mechanism:
Common detergents are categorized into three groups based on physical characteristics: Non-Ionic Detergents, Ionic Detergents, and Zwitterionic Detergents
Image 1: Detergents often fall into 3 categories: nonionic, ionic, and zwitterionic
Neutralization:
Ionic Detergents [2]: Ionic detergents are comprised of a hydrophobic hydrocarbon chain and a hydrophilic polar head group which contain either a negative (anionic) or positive (cationic) charge. Ionic detergents are widely used for the complete disruption of cellular structures, dissociation of protein-protein interactions and denaturation of proteins for separation during gel electrophoresis.
- Anionic Detergents: Anionic detergents typically have negatively charged sulfate groups as the hydrophilic head. Examples of anionic detergents are as given below:
- Sodium Cholate Hydrate
- Sodium Deoxycholate
- Sodium Dodecyl Sulfate (SDS)
- Sodium Glycocholate
- Sodium Glycodeoxycholate
- Sodium Lauroylsarcosinate
- Sodium Taurocholate
- Sodium Taurodeoxycholate
- Cationic Detergents: Cationic detergents contain a positively charged ammonium group, and include:
- Cetyltrimethylammonium Bromide (CTAB)
Non-ionic Detergents [2]: Non-ionic detergents have uncharged hydrophilic headgroups. They are considered mild surfactants as they break protein-lipid and lipid-lipid associations, but not protein-protein interactions. They do not denature proteins, thus resulting solubilization of membrane proteins in their native and active form without altering their protein interactors. This detergent type includes the following:
- Brij 35
- n-Decyl β-D-glucopyranoside
- n-Decyl-β-D-maltopyranoside
- Digitonin
- n-Dodecyl β-D-glucopyranoside
- Hexyl β-D-glucopyranoside
- IGEPAL CA-630
- n-Octyl β-D-galactopyranoside
- n-Octyl β-D-glucopyranoside
- n-Octyl-β-D-thioglucopyranoside
- Pluronic F-68 (Poloxamer 188)
- Pluronic F-127 (Poloxamer 407)
- Saponin
- Triton X-100
- Triton X-114
- Tween-20 or Polysorbate-20
- Tween-80 or Polysorbate-80
Zwitterionic: Zwitterionic detergents contain both negatively and positively charged atomic head groups in equal numbers, resulting in zero net charge. These detergents have characteristics of both ionic and non-ionic types.
- Like non-ionic detergents, zwitterionic detergents have a neutral net charge and are thus can be used as alternatives to non-ionic detergents in biological applications such as ion-exchange chromatography, electrophoresis, and isoelectric focusing.
- Similar to ionic detergents, they zwitterionic detergents are more efficient at breaking protein-protein bonds. However, the extent to which the Zwitterionic detergents break the protein bonds is less harsh and are thus efficient in maintaining the native state and charge of the individual proteins.
Examples of Zwitterionic Detergents can include:
- CHAPS: {3-[(3-Cholamidopropyl) dimethylammonio propane sulfonate)]}
- CHAPSO: {(3-Cholamidopropyl) dimethylammonio]-2-hydroxy-1-propanesulfonate}
Detergent Mechanism: Sodium Dodecyl Sulfate
Sodium Dodecyl Sulfate (SDS) also known as Sodium lauryl sulfate, is an anionic detergent and is widely used in various scientific applications, such as biochemical, molecular biology, and cell biology research [3].
SDS is a well-known example of a detergent solution that has a direct impact on the denaturation of proteins, disruption of cell membranes, and electrophoresis. SDS is a key component of SDS-PAGE and a variety of other experiments. With a hydrophobic tail, a hydrophilic polar head, and a positively charged sodium ion, SDS dissociates in aqueous environments and leaves a net negative charge around proteins of interest.
The unique structure of SDS allows it to break hydrophobic interactions and hydrogen bonding within a protein’s native structure, as well as coat proteins in a uniform negative charge, forcing a linear protein chain and preventing stability and folding. This process is a key step in electrophoresis as fully denatured proteins are much more effective in migrating through polyacrylamide gel.
Image 1: The mechanism of SDS involves the leveraging of hydrophobic and hydrophilic structures to denature and apply a uniform negative charge to proteins.
Examples of the widely used detergents:
Similar to Sodium Dodecyl Sulfate (SDS), many other detergents employ unique mechanisms dependant on their molecular structure. Other detergent types commonly seen within biochemistry experimentation include…
Triton X-100: Triton X-100 is a non-ionic and non-denaturing detergent that preserves the native structure and activity of proteins by forming micelles around them. Triton X-100 is often used for cell lysis, membrane protein extraction, and immunoprecipitation. It can also be used for permeabilizing cells for transfection, immunofluorescence staining, and for the preparation of cell sections for electron microscopy.
NP-40 (Nonidet P-40): NP-40 is a non-ionic, non-denaturing detergent similar to, but slightly less potent than Triton X-100, and can reduce protein aggregation and nonspecific binding. NP-40 is suitable for cell lysis, membrane protein solubilization, purification of membrane protein complexes, and immunostaining. NP-40 and IGEPAL CA-630 are chemically indistinguishable or are rather chemically identical.
Tween-20: Tween 20 also known as Polysorbate-20 is a non-ionic detergent that belongs to the polyethylene glycol (PEG) family. Tween 20 is a surfactant that can lower the surface tension of aqueous solutions and increase their solubility. Tween 20 is mainly used for blocking and washing steps in immunoassays, such as ELISA, immunohistochemistry and Western blotting.
CHAPS: CHAPS is a zwitterionic detergent that has both positive and negative charges on its polar head group. CHAPS is a mild detergent compatible with most proteins and enzymes. It is frequently used for solubilizing membrane proteins and lipids, along with protein purification by chromatography. CHAPS is also used in mass spectrometry, isoelectric focusing and two-dimensional gel electrophoresis (2D-PAGE).
Strong Acids and Bases
Detergent Solutions at Boston BioProducts
Every detergent solution is unique to the analyte used and the experimental application. Select the appropriate detergent solution from the catalog or design your optimal formulation with custom manufacturing options at Boston BioProducts.
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References:
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- Linke, D. (2009). Detergents: An overview. In J. N. Abelson, M. I. Simon, & R. J. Lefkowitz (Eds.), Methods in enzymology: Volume 463. G protein-coupled receptors (pp. 603–616). Academic Press.
- Bury, C. R., & Browning, J. (1968). Comparison of ionic and non-ionic detergents. Journal of the Society of Cosmetic Chemists, 19(11), 803-810. Comparison of ionic and non-ionic detergents - Transactions of the Faraday Society (RSC Publishing)
- Singer, M. M., & Tjeerdema, R. S. (1993). Fate and effects of the surfactant sodium dodecyl sulfate. Reviews of Environmental Contamination and Toxicology, 133, 95-149. Fate and Effects of the Surfactant Sodium Dodecyl Sulfate | SpringerLink