Biomaterial Database

Efficient precipitation and accurate quantitation of detergent-solubilized membrane proteins. 1992

Y C Chang

Institute of Life Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.

The protein assay method of I. Polacheck and E. Cabib (Anal. Biochem. 117, 311-314, 1981) has been modified to provide a general method for quantitating protein samples in the presence of detergents. Dilute detergent-solubilized membrane proteins, by using ribonucleic acid as a carrier, have been efficiently precipitated here by trichloroacetic acid (TCA) in the presence of sodium dodecyl sulfate (SDS). Washing the pellets once with TCA solution has removed most of the reagents present in the original sample. The washed sample could then be quantitated by the Lowry method (O. J. Lowry, N. J. Rosebrough, A. L. Farr, and R. J. Randall, J. Biol. Chem. 193, 265-275, 1951). This procedure could be used to assay protein solutions of a concentration as low as 5 micrograms/ml in the presence of the following reagents: Triton X-100, Triton X-114, Tween 20, N-octylglucoside, deoxycholate, cholate, Thesit, octanoyl-N-methylglucamide, isotridecylpoly (ethyleneglycoether)n, Nonidet P-40, glucose, methyl-D-glucopyranoside, methyl-D-mannopyranoside, N-acetyl-glucosamine, Mn2+, Ca2+, Mg2+, and many buffer reagents. Proteins solubilized from porcine brain myelin sheath and synaptic plasma membranes were quantitated by amino acid analysis and by the TCA/SDS precipitation method described here. The resultant protein concentrations were almost identical. The results have suggested this TCA/SDS precipitation method to be useful for quantitating dilute protein samples containing high concentrations of detergents and other reagents commonly employed in studying membrane proteins.

UI	MeSH Term	Description	Entries
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
D009186	Myelin Sheath	The lipid-rich sheath surrounding AXONS in both the CENTRAL NERVOUS SYSTEMS and PERIPHERAL NERVOUS SYSTEM. The myelin sheath is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (SCHWANN CELLS in the peripheral and OLIGODENDROGLIA in the central nervous system). Deterioration of the sheath in DEMYELINATING DISEASES is a serious clinical problem.	Myelin,Myelin Sheaths,Sheath, Myelin,Sheaths, Myelin
D011232	Chemical Precipitation	The formation of a solid in a solution as a result of a chemical reaction or the aggregation of soluble substances into complexes large enough to fall out of solution.	Precipitation, Chemical
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003902	Detergents	Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.	Cleansing Agents,Detergent Pods,Laundry Detergent Pods,Laundry Pods,Syndet,Synthetic Detergent,Agent, Cleansing,Agents, Cleansing,Cleansing Agent,Detergent,Detergent Pod,Detergent Pod, Laundry,Detergent Pods, Laundry,Detergent, Synthetic,Detergents, Synthetic,Laundry Detergent Pod,Laundry Pod,Pod, Detergent,Pod, Laundry,Pod, Laundry Detergent,Pods, Detergent,Pods, Laundry,Pods, Laundry Detergent,Synthetic Detergents
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012995	Solubility	The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Solubilities
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse