Biomaterial Database

Measurement of microgram quantities of protein by a generally applicable turbidimetric procedure. 1988

J C Vera

Instituto de Bioquímica, Universidad Austral de Chile, Valdivia.

A modified turbidimetric method for protein determination which involves the use of trichloroacetic acid as the precipitating agent is described. Maximal turbidity develops in less than 30 min and is stable for at least 120 min. A linear relationship between turbidity at 340 nm and protein concentration is observed between 2 and 40 micrograms protein. Sodium dodecyl sulfate is added to avoid the interference by nonionic and cationic detergents and lipids and to decrease the protein-to-protein variation. The use of cetyltrimethyl ammonium bromide provides a two-step procedure to correct for the contribution of contaminating nucleic acid. Many compounds which interfere with other protein quantitation methods have no effect on this system. The interference of commonly used reagents as sucrose and urea can be easily corrected. This procedure compared favorably with the most widely used protein quantitation methods in simplicity, sensitivity, and specificity.

UI	MeSH Term	Description	Entries
D009391	Nephelometry and Turbidimetry	Chemical analysis based on the phenomenon whereby light, passing through a medium with dispersed particles of a different refractive index from that of the medium, is attenuated in intensity by scattering. In turbidimetry, the intensity of light transmitted through the medium, the unscattered light, is measured. In nephelometry, the intensity of the scattered light is measured, usually, but not necessarily, at right angles to the incident light beam.	Turbidimetry,Nephelometry,Turbidimetry and Nephelometry
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
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D002593	Cetrimonium Compounds	Cetyltrimethylammonium compounds that have cationic detergent, antiseptic, and disinfectant activities. They are used in pharmaceuticals, foods, and cosmetics as preservatives; on skin, mucous membranes, etc., as antiseptics or cleansers, and also as emulsifiers. These compounds are toxic when used orally due to neuromuscular blockade.	Cetyltrimethylammonium Compounds,Cetrimides,Compounds, Cetrimonium,Compounds, Cetyltrimethylammonium
D000077286	Cetrimonium	Cetyltrimethylammonium compound whose salts and derivatives are used primarily as topical antiseptics.	1-Hexadecyltrimethylammonium Chloride,CTAB,CTAOH,Cetavlon,Cetrimide,Cetriminium,Cetrimonium Bromide,Cetrimonium Chloride,Cetrimonium Hydroxide,Cetrimonium Iodide,Cetrimonium Methosulfate,Cetrimonium Methyl Sulfate,Cetrimonium Monosulfate,Cetyltrimethylammonium Bromide,Cetyltrimethylammonium Chloride,HTAB Cpd,Hexadecyl Trimethyl Ammonium Bromide,Hexadecyl(trimethyl)azanium,Hexadecyltrimethylammonium Bromide,Hexadecyltrimethylammonium Octylsulfonate,Octylsulfonate, Hexadecyltrimethylammonium
D012313	RNA	A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	RNA, Non-Polyadenylated,Ribonucleic Acid,Gene Products, RNA,Non-Polyadenylated RNA,Acid, Ribonucleic,Non Polyadenylated RNA,RNA Gene Products,RNA, Non Polyadenylated
D012967	Sodium Dodecyl Sulfate	An anionic surfactant, usually a mixture of sodium alkyl sulfates, mainly the lauryl; lowers surface tension of aqueous solutions; used as fat emulsifier, wetting agent, detergent in cosmetics, pharmaceuticals and toothpastes; also as research tool in protein biochemistry.	Sodium Lauryl Sulfate,Irium,Dodecyl Sulfate, Sodium,Lauryl Sulfate, Sodium,Sulfate, Sodium Dodecyl,Sulfate, Sodium Lauryl
D014238	Trichloroacetic Acid	A strong acid used as a protein precipitant in clinical chemistry and also as a caustic for removing warts.	Acide trichloracetique,Rubidium Trichloroacetate,Sodium Trichloroacetate,Acid, Trichloroacetic,Trichloroacetate, Rubidium,Trichloroacetate, Sodium,trichloracetique, Acide