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  Destructible surfactants and uses thereofUSPTO Application #: 20080027234Title: Destructible surfactants and uses thereof Abstract: Destructible surfactants and methods of using same are provided. The invention includes anionic surfactants having a dioxolane or dioxane functional group which enables the surfactant to be broken down under acidic conditions. The invention also includes methods of making anionic surfactants and methods of using anionic surfactants in a variety of applications. (end of abstract)
Agent: Edwards Angell Palmer & Dodge LLP Client: Waters Corporation - Boston, MA, US Inventors: Peter Jeng Jong Lee, Bruce J. Compton USPTO Applicaton #: 20080027234 - Class: 549372000 (USPTO) Related Patent Categories: Organic Compounds -- Part Of The Class 532-570 Series, Azo Compounds Containing Formaldehyde Reaction Product As The Coupling Component, Carbohydrates Or Derivatives, Oxygen Containing Hetero Ring (e.g., Dioxirane, Etc.), The Hetero Ring Is Six-membered, Plural Ring Oxygens In The Hetero Ring (e.g., 1,2-dioxin, Etc.), The Ring Oxygens Are In The 1,3-positions Of The Hetero Ring (e.g., 1,3 Dioxane, Etc.), The Patent Description & Claims data below is from USPTO Patent Application 20080027234. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] This invention relates generally to compositions and methods for analysis and purification of large molecules, such as proteins or peptides. In particular, this invention relates to anionic surfactants which can be destroyed at relatively low pH and methods which use these surfactants. Examples of applications which will benefit from this invention include electrophoresis, ion-pair liquid chromatography, liquid chromatography, mass spectrometric detection, liquid-liquid extraction and other techniques which benefit from the initial presence and ultimate removal of a surfactant. BACKGROUND OF THE INVENTION [0002] Surfactants are used in a variety of applications. For example, surfactants are used commercially for cleaning manufactured items, removing paints, chemical processing, for use in emulsion polymerization, solubilizing drugs, purifying proteins, and various bioanalytical applications. [0003] One particular bioanalytical application that uses surfactants is sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In the past three decades, SDS-PAGE has been widely used as a simple and relatively rapid tool for analysis and purification of large molecules such as proteins (U.K. Laemmli, Nature 227, 680-685, 1970). Sodium dodecylsulfate (SDS) is an anionic surfactant that denatures proteins by forming a stable complex. Upon denaturation, SDS binds to most proteins and peptides in a constant weight ratio of about 1.4:1. As a result, the SDS-protein complexes have almost identical charge densities and therefore migrate in a polyacrylamide gel according to molecular weight. If the gel is of the correct porosity, a plot of log M.sub.w vs. relative mobility, R.sub.f, results in a linear relationship. The band intensity after staining is a rough indicator of the amount present in the sample. When coupled with another electrophoretic technique, isoelectricfocusing, SDS-PAGE can separate complex mixtures into several hundred discrete components. [0004] The ability to estimate the size and amount of a protein has led to various applications of SDS-PAGE. However, there are some drawbacks to the technology. For example, it is very difficult to use mass spectrometry to monitor and analyze samples from DS-PAGE separations because SDS interferes with the sensitivity of mass spectrometry detection. Furthermore, it is very difficult to separate SDS from SDS/protein complex since SDS is a surfactant that forms emulsions. [0005] Several approaches have been tried to solve these problems. Non-ionic surfactants, such as octyl .beta.-glucopyranoside, have been used for mass spectrometric applications (P. Dainese Hatt, M. Quadroni, W. Staudenmann, and P. James, Eur. J. Biochem. 246, 336-343, 1997). However, the electrophoretic separation still requires SDS, and a time-consuming surfactant exchange step is needed. [0006] Another approach is electroelution or electroblotting from the polyacrylamide gel onto a PVDF or nitrocellulose membrane. However, this approach often leads to significant loss in protein recovery. [0007] Other approaches that have been tried are also time-consuming and may lead to significant protein loss are: protein precipitation with guanidium chloride (J. E. Schively, in Methods of protein microcharacterization; J. E. Schively, Ed., Humana Press, Clifton, N.J., 1986, p. 41.), ion-pair reagents (W. H. Koningsberg and L. H. Henderson. Methods Enzymol. 91, 254, 1983), liquid-liquid extraction (P. Davidsson, A. Westman, M. Puchades. C. L. Nilsson, and K. Blennow, Anal. Chem. 71, 642-647, 1999) and reversed-phase HPLC (H. Kawasaki and K. Suzuki, Anal. Biochem. 186, 264, 1990). SUMMARY OF THE INVENTION [0008] The present invention features destructible surfactants and methods for solubilizing, analyzing, separating, purifying and/or characterizing large molecules with these surfactants. In one aspect, the invention provides anionic surfactants which may be selectively broken up at relatively low pH. The resulting breakdown products of the surfactants may be removed from the sample with relative ease. The invention has applicability in a variety of techniques which benefit from the initial presence and ultimate removal of a surfactant. [0009] The invention provides surfactants represented by the formula (Formula I): [0010] in which [0011] p is 0, 1 or 2; [0012] R is alkyl; [0013] R.sub.1 and R.sub.2 are each, independently, hydrogen or methyl; and [0014] R.sub.3 is selected from --OSO.sub.3.sup.-, --R.sub.4OSO.sub.3.sup.-, --R.sub.4OR.sub.5SO.sub.3.sup.-, and --OR.sub.5SO.sub.3.sup.-, [0015] wherein R.sub.4 and R.sub.5 are each, independently, lower alkyl. [0016] The invention also includes methods of preparing surfactants having the structure of Formula I. [0017] In one embodiment, the invention pertains to methods for analyzing a sample which include contacting the sample with a surfactant having the structure of Formula I. In a preferred embodiment, the method includes analyzing the sample by high performance liquid chromatography. In another preferred embodiment, the method includes analyzing the sample by mass spectrometry. In yet another preferred embodiment, the method includes analyzing the sample by ion-pair liquid chromatography. [0018] In another embodiment, the invention provides a method for performing electrophoresis which includes contacting a sample with a surfactant having the structure of Formula I. In a preferred embodiment, the electrophoresis is gel electrophoresis, more preferably polyacrylamide gel electrophoresis, including the tube, slab gel and capillary formats of polyacrylamide gel electrophoresis. In other preferred embodiments, the electrophoresis is free zone electrophoresis or capillary electrophoresis. In still other preferred embodiments, the methods include the step of degrading the surfactant after electrophoresis. In another preferred embodiment, the method includes degrading the surfactant after electrophoresis with a relatively acidic solution. In yet another preferred embodiment, the method includes the step of further purifying the sample after degrading the surfactant. [0019] In still another embodiment, the invention provides a kit for performing electrophoresis which includes a surfactant having the structure of Formula I. In a preferred embodiment, the kit includes a component for degrading the surfactant. In another preferred embodiment, the kit includes a molecular weight standard. In still another preferred embodiment, the kit includes a staining reagent. In another embodiment, the surfactant of the invention is incorporated into a gel medium. BRIEF DESCRIPTION OF THE DRAWINGS [0020] FIG. 1 depicts a plot of log.sub.10 molecular weight (MW) versus relative migration factor (Rf) for Mark VI and Mark VII proteins using the data for SDS and ALS-I from Example 2. Continue reading... Full patent description for Destructible surfactants and uses thereof Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Destructible surfactants and uses thereof patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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