Search results
Results from the WOW.Com Content Network
The ideal salt for protein precipitation is most effective for a particular amino acid composition, inexpensive, non-buffering, and non-polluting. The most commonly used salt is ammonium sulfate . There is a low variation in salting out over temperatures 0 °C to 30 °C.
As different proteins have different compositions of amino acids, different protein molecules precipitate at different concentrations of salt solution. [citation needed] Unwanted proteins can be removed from a protein solution mixture by salting out as long as the solubility of the protein in various concentrations of salt solution is known.
Millon's reagent is an analytical reagent used to detect the presence of soluble proteins. A few drops of the reagent are added to the test solution, which is then heated gently. A reddish-brown coloration or precipitate indicates the presence of tyrosine residue which occur in nearly all proteins. [1]
Ammonium sulfate precipitation is a useful technique as an initial step in protein purification because it enables quick, bulk precipitation of cellular proteins. [4] It is also often employed during the later stages of purification to concentrate protein from dilute solution following procedures such as gel filtration .
In an aqueous solution, precipitation is the "sedimentation of a solid material (a precipitate) from a liquid solution". [1] [2] The solid formed is called the precipitate. [3] In case of an inorganic chemical reaction leading to precipitation, the chemical reagent causing the solid to form is called the precipitant. [4]
The Bradford protein assay (also known as the Coomassie protein assay) was developed by Marion M. Bradford in 1976. [1] It is a quick and accurate [2] spectroscopic analytical procedure used to measure the concentration of protein in a solution. The reaction is dependent on the amino acid composition of the measured proteins.
Precipitating (or denaturing) fixatives act by reducing the solubility of protein molecules and often by disrupting the hydrophobic interactions that give many proteins their tertiary structure. The precipitation and aggregation of proteins is a very different process from the crosslinking that occurs with aldehyde fixatives.
Salting in refers to the effect where increasing the ionic strength of a solution increases the solubility of a solute, such as a protein. This effect tends to be observed at lower ionic strengths. [citation needed] Protein solubility is a complex function of physicochemical nature of the protein, pH, temperature, and the concentration of the ...