The micelle formation process can be described by the following equation:

m * S <=> S_m

where m is the average association number S the concentration of monomeric surfactant and S_m

The most complete listing of critical micelle concentrations can be found in the United States Department of Commerce Publication [20]. Additional data from the relevant literature have been included in the product description.

One class of additives are proteins. Their interaction with surfactant systems has received increasing attention in recent years, both for normal [21] and reversed micelles [22].

Analytical Information

Since the alkyl chain length of a surfactant has a decisive influence on its physicochemical properties and hence on various biochemical applications [23, 24], each surfactant has been analyzed with respect to the uniformity of the alkyl chain by various techniques such as TLC, HPLC, GC (after hydrolysis). Some traditional surfactants, such as the Triton-series, are mixtures of a variety homologues and must correspond to the standard mixture. Surfactants consisting of only one species are characterized by a minimum purity assay which refers to the chain homologue purity. Each surfactant is further checked for appearance, solubility, identity (by FT-IR and/or NMR) and relevant trace impurities such as the respective starting material, peroxides, UV-absorbing foreign materials and metal traces (by ICP-AES). The stereochemical purity is checked by measuring optical rotation.

Applications

The surfactants (see [25] for the difference between detergent and surfactant) are of widespread importance in the detergent industry, in emulsification, lubrication, catalysis, tertiary oil recovery, and in drug delivery.

• In biochemistry, the practical as well as theoretical importance of surfactants may be illustrated with the following examples: Surfactants have allowed the investigation of molecular properties of membrane proteins and lipoproteins, acting as solubilizing agents and as probes for hydrophobic binding sites [26]. The properties of surfactants, as well as further facts relevant to the particular experiments, must be carefully considered [27-29]. Surfactants have successfully contributed to the purification of receptors in their active forms [30], such as the neuropeptide receptors [31] and opiate receptors [32]. All holoreceptor- complex and reaction- center isolations require the use of a surfactant in order to separate the integral protein systems from the rest of the membrane [33].
• Surfactants have been used in the investigation of the denaturation of bacteriorhodopsin [34] and in thermal stability experiments of rhodopsin [35].
• The operations of exchange [36] and removal [37] of surfactants bound to membrane proteins are crucial and have been successfully applied to a wide variety of these proteins.
• The effects of surfactants on the function of membrane-bound enzymes such as cytochrome P-450 [38] and (Na⁺ + K⁺)-ATPase [39] have also been determined.
• Integral membrane proteins can be separated from hydrophilic proteins and identified as such in crude surfactant extracts of membrane or cells [40].
• Methods for the solubilization of low-density lipoproteins have advanced the understanding of the assembly, interconversion and molecular exchange processes with plasma lipoproteins [41].
• In electrophoresis, various techniques require the use of surfactants. The popular techniques of SDS-PAGE for the identification and subunit molecular weight estimation of proteins is based on a specific type of surfactant-protein interaction [42]. 2D-PAGE uses SDS in one direction and Triton X-100 in the other. This technique has been used to identify proteins containing long hydrophobic regions [44] and relies on the different binding ability of non-ionic surfactants to water-soluble and intrinsic membrane proteins. Isoelectric focusing [45], native electrophoresis and blotting [46] are other electrophoretic techniques which may need surfactants for the solubilization or transfer of membrane proteins.
• In high performance liquid chromatography, common techniques such as ion-exchange HPLC, reversed-phase HPLC and sizeexclusion-HPLC may require surfactants to solubilize membrane proteins [47 48]. Ionpair HPLC requires surfactants as reagents in order to achieve the separation conditions (ionpairing) [49, 50].
• Affinity surfactants have been used as reversibly bound ligands in high performance affinity chromatography [51].
• Crystallization of membrane proteins was achieved using short chain surfactants, which are believed to shield the hydrophobic intermembrane part of the molecule. Thus the polar interactions betvveen individual molecules come into play, providing the stabilizing force in crystallization [52].
• Surfactants are also employed to promote the dissociation of proteins from nucleic acids on extraction from biological material.
• Further applications of surfactants in biochemistry are the solubilization of enzymes in apolar solvents via reversed micelles [53] and the isolation of hydrophobic proteins [54].

In analytical chemistry, surfactants have been recognized as being very useful for improving analytical methodology, e.g. in chromatography and luminiescence spectroscopy [55, 56]. For applications requiring highest quality products, we offer a range of BioChemika Ultra standard precipitation reagents.

References

1. F. Kraft, Ber. 29, 1334 (1896).
2. C.Tanford, the Hydrophobic Effect, 2nd ed., Wiley, New York (1980).
3. K.A. Dill, P. Flory, Proc. Natl. Acad. Sci. 78, 676 (1981).
4. K. Shinoda, Solvent Properties of Surfactant Solutions, M. Dekker, New York (1967); K. Shinoda et al., Colloidal Surfactants, Academic Press, New York (1963).
5. J.H. Fendler, E.J. Fendler, Catalysis in Micellar and Macromolecular Systems, Academic Press, New York (1975).
6. Nonionic Surfactants (M.J. Schick ed.), M. Dekker, New York (1967).
7. Cationic Surfactants (E. Jungermann, ed.) M. Dekker, New York (1970).
8. Anionic Surfactants (W.M. Linfield, ed.), M. Dekker, New York (1973).
9. M.J. Rosen, Surfactants and Interfacial Phenomena, Wiley, New York (1978).
10. Micellization, Solubilization and Microemulsions (K.L. Mittal ed.), Plenum Press, New York (1977).
11. Solution Chemistry of Surfactants (K.L. Mittal, ed.), Plenum Press, New York (1979).
12. Solutions Behaviour of Surfactants: Theoretical and Applied Aspects (K.L. Mittal, E.J.Fendler, eds.), Plenum Press, New York (1982).
13. Surfactants in Solution (K.L. Mittal, B. Lindman eds.), Plenum Press, New York (1984).
14. ModernTrends of Colloid Science in Chemistry and Biology (H.E. Eicke, ed.), Birkhduser, Basel (1985).
15. P.L. Luisi, B. Straub, Reverse Micelles -Technological and Biological Relevance, Plenum Press, New York (1984).
16. J.H. Fendler, Membrane Mimetric Chemistry, Wiley, New York (1982).
17. K. Shinoda, S. Friberg, Emulsion and Solubilization, Wiley, New York (1986).
18. H.F. Eicke, J. Colloid Interface Sci. 68, 440 (1979)
19. J. Tabony et al., Nature 327, 321 (1987).
20. P. Mukerjee, K.J. Mysels, Critical Micelle Concentrations of Aqueous Surfactant Systems, NSRDS-NBS, 36 (1971).
21. J.A. Reynolds, Methods Enzymol. 61, 58 (1979).
22. RL. Luisi, Angew. Chem. 97, 439 (1985).
23. M.M. Marqulies, H.L.Tiffany, Anal. Biochem. 136, 309 (1984).
24. S.A. Lacks et al., Anal. Biochem. 100, 357 (1979)
25. S.A. Lacks et al., Anal. Biochem. 100, 357 (1979)
26. C. Tanford, J.A. Reynold, Biochem. Biophys. Acta 457, 133 (1976).
27. A. Helenius et al., Methods Enzymol. 56, 734 (1979).
28. L.M. Hjelmeland, A. Chrambach, Methods Enzymol. 104, 305 (1984).
29. L.M. Hjelmeland, Methods Enzymol. 124, 135 (1986).
30. Membranes, Detergents and Receptor Solubilization (J.C.Venter, L.C. Harrison, ed.), A.R. Liss, New York (1984).
31. M. H. Perrin, Methods Enzymol. 124, 164 (1986).
32. R.S. Zukin, R. Maneckjee, Methods Enzymol. 124, 172 (1986).
33. P..A. Loach, Methods Enzymol. 69, 155 (1980).
34. E. London, H.G. Khorana, J. Biol. Chem. 257, 7003 (1982).
35. W.J. de Grip, Methods Enzymol. 81, 256 (1982).
36. W.C. Robinson et al., Biochemistry 23, 6121 (1984).
37. S.E. Laursen et al., Anal. Biochem. 153, 387 (1986); B. Kaplan, M. Ras, J. Chromatogr. 423, 376 (1987).
38. L.S. Kaminsky et al., Biochemistry 26, 1276 (1987).
39. W.H. Huang et al., J. Biol. Chem. 260, 7356 (1985).
40. C. Bordier, J. Biol. Chem. 256, 1604 (1981).
41. M.T. Walsh, D. Atkinson, Methods Enzymol. 128, 582 (1986).
42. T. B. Nielsen, J. A. Reynolds, MethoUs Enzymol. 48, 3 (1978).
43. O.J. Bjerrum et al., Electrophoresis 8, 388 (1987).
44. A. Helenius, K. Simons, Proc. Natl. Acad. Sci. 74, 529 (1977).
45. P.G. Righetti, Isoelectric Focusing, Elsevier, Amsterdam (1983).
46. Electrophoresis (O.J. Bjerrum B.J. Radola, ebs.), vol. 9 (1987).
47. J.P. Andersen et al ., Biochemistry 25, 6439 (1986).
48. G.W. Welling, J. Chromatogr 418, 223 (1987).
49. lon-Pair Chromatography (M.T. Hearn, ed.), M. Dekker, New York (1985).
50. High Performance Liquid Chromatography in Biochemistry (A. Henschen et al., eds.), Verlag Chemie, Weinheim (1985).
51. J.L.Torres et al., Anal. Biochem. 171, 411 (1988).
52. L.J. Delucas, C.E. Bugg,Trends in Biotechnology 7, 188 (1987).
53. P. L. Luisi, C. Laane Trends in Biotechnology 6, 153 (1986).
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Alphabetical List of Products

A-H   L-Z

Catalog No.	Name	see
	A-H
	AOT	Docusate sodium salt
	Benzethoniumchloride	Hyamine® 1622
	Bis(2-ethylhexyl) sulfosuccinate sodium salt	Docusate sodium salt
	Bishydroxyethylether	Diethylene glycol
29337	Cetrimide	Hexadecyltrimethylammonium bromide
	Cetrimonium bromide	Hexadecyltrimethylammonium bromide
	Cetyltrimethylammonium bromide	Hexadecyltrimethylammonium bromide
	Cholic acid sodium salt	Sodium cholate
26978	Choline chloride
	CTAB	Hexadecyltrimethylammonium bromide
	DDAO	N,N-Dimethyldecylamine-N-oxide solution
	DDAO	N,N-Dimethyldodecylamine-N-oxide solution
	7-Deoxycholic acid sodium salt	Sodium deoxycholate
	Desoxycholic acid sodium salt	Sodium deoxycholate
93171	Diethylene glycol
	Diglycol	Diethylene glycol
	3alpha,12alpha-Dihydroxy-5beta-cholanic acid sodium salt	Sodium deoxycholate
40105	N,N-Dimethyldecylamine-N-oxide solution
40231	N,N-Dimethyldodecylamine-N-oxide solution
	Dioctyl sulfosuccinate sodium salt	Docusate sodium salt
86139	Docusate sodium salt
	N-Dodecanoyl-N-methylglycine sodium salt	'N-Lauroylsarcosine
	Dodecyl lithium sulfate	Lithium dodecyl sulfate
	Dodecyl sodium sulfate	Sodium dodecyl sulfate
	Dodecyl sulfate lithium salt	Lithium dodecyl sulfate
	Dodecyl sulfate sodium salt	Sodium dodecyl sulfate
52365	Hexadecyltrimethylammonium bromide for molecular biology
52369	Hexadecyltrimethylammonium bromide
88571	1,6-Hexanediol solution
53751	Hyamine® 1622
	(2-Hydroxyethyl)trimethylammonium chloride	Choline chloride
	2-Hydroxyethyl ether	Diethylene glycol
Catalog No.	Name	see
	L-Z
61743	N-Lauroylsarcosine sodium salt for molecular biology
61744	N-Lauroylsarcosine sodium salt
	Lauryl sulfate sodium salt	Sodium dodecyl sulfate
	Lauryldimethylamine N-oxide	N,N-Dimethyldodecylamine-N-oxide solution
	LDAO	N,N-Dimethyldodecylamine-N-oxide solution
62554	Lithium dodecyl sulfate
	Lithium lauryl sulfate	Lithium dodecyl sulfate
	2,2'-Oxydiethanol	Diethylene glycol
	Palmityltrimethylammonium bromide	Hexadecyltrimethylammonium bromide
95172	Polyethylene glycol
	Sarkosyl NL	N-Lauroylsarcosine
	SDS	Sodium dodecyl sulfate
	Sodium bis(2-ethylhexyl) sulfosuccinate	Docusate sodium salt
	Sodium lauryl sulfate	Sodium dodecyl sulfate
71386	Sodium chloride solution for molecular biology
27027	Sodium cholate hydrate
30968	Sodium deoxycholate monohydrate
	Sodium N-dodecanoyl-N-methylglycinate	'N-Lauroylsarcosine
71725	Sodium dodecyl sulfate for molecular biology
71727	Sodium dodecyl sulfate
05030	Sodium dodecyl sulfate solution for molecular biology
71736	Sodium dodecyl sulfate solution for molecular biology
	Sodium N-lauroylsarcosinate	'N-Lauroylsarcosine
	Sulfobutanedioic acid bis(2-ethylhexyl ester) sodium salt	Docusate sodium salt
	Sulfosuccinic acid bis(2-ethylhexyl) ester sodium salt	Docusate sodium salt
	TPE buffer solution	TRIS phosphate-EDTA buffer solution
	3alpha,7alpha,12alpha-Trihydroxy-5beta-cholanic acid sodium salt	Sodium cholate
93391	TRIS phosphate-EDTA buffer solution for molecular biology
93443	Triton® X-100 solution for molecular biology