Ellman’s reagent has been widely used for the quantitation of thiols in peptides and proteins. It has also been used to assay disulfides present after blocking any free thiols (e.g., by carboxymethylation) and reducing the disulfides prior to reaction with the reagent. It is also commonly used to check the efficiency of conjugation of sulfhydryl- …
DNA, RNA, and protein strongly absorb ultraviolet light in the 260 to 280 nm range. UV spectroscopy can be used as a quantitative technique to measure nucleic acid concentration and protein contamination. Nucleic acids strongly absorb at 260 nm and less strongly at 280 nm while proteins do the opposite. The general rules for determining …
Bradford method is a common colorimetric method to determine protein concentration in a sample solution. The Bradford method of protein determination is based on the binding of a dye, Coomasie Blue G, to the protein. This binding shifts the absorption maximum of the dye from red to blue. The absorbance of the solution is measured …
The Bicinchoninic acid (BCA) assay first was described by Smith, et al. BCA assay is similar to Lowry assay since it also depends on the conversion of Cu(2+) to Cu(+) under alkaline conditions. The Cu(+) is then detected by reaction with BCA. The reaction results in the development of an intense purple color with an …
After amplify DNA template using PCR method, now you can continue your work by using gel electrophoresis in a gel composed of agarose in order to separate DNA fragments based on its molecular weight. The percentage of agarose used depends on the size of fragments to be resolved. In general a 0.8-1% gel may be …
After it is extracted from particular sources, nucleic acid must be stored either for archival purposes or before assay performance. The principle of nucleic acid storage is prevention of enzymatic or physical damage to the purified product. In order to overcome those problems we have three options of method to store our purified nucleic acid: …
It is possible to estimate protein concentration in a solution by using simple spectrometer. Absorption of radiation in the near UV (280 nm) by proteins depends on the Tyrosine and Tryptophan content (also to a very small extent on the amount of Phenylalanine and disulfide bond).