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Note 2: Denaturation can occur when proteins and nucleic acids are subjected to elevated temperature or to extremes of pH, or to nonphysiological concentrations of salt, organic solvents, urea, or other chemical agents. Note 3: An enzyme loses its ability to alter or speed up a chemical reaction when it is denaturized. [2]
Pepsin is inactive at pH 6.5 and above, however pepsin is not fully denatured or irreversibly inactivated until pH 8.0. [11] [15] Therefore, pepsin in solutions of up to pH 8.0 can be reactivated upon re-acidification. The stability of pepsin at high pH has significant implications on disease attributed to laryngopharyngeal reflux. Pepsin ...
To maintain this defined three-dimensional structure, proteins rely on various types of interactions between their amino acid residues. If these interactions are interfered with, for example by extreme pH values, high temperature or high ion concentrations, this will cause the enzyme to denature and lose its catalytic activity. [citation needed]
Protein precipitation is widely used in downstream processing of biological products in order to concentrate proteins and purify them from various contaminants. For example, in the biotechnology industry protein precipitation is used to eliminate contaminants commonly contained in blood. [1]
The most famous example is the hyperchromicity of DNA that occurs when the DNA duplex is denatured. [1] The UV absorption is increased when the two single DNA strands are being separated, either by heat or by addition of denaturant or by increasing the pH level. The opposite, a decrease of absorbance is called hypochromicity.
Tris(2-carboxyethyl)phosphine is an alternative reducing agent that is more stable and effective at low pH, but it is bulky and reduces cystines in folded proteins only slowly. [6] DTT's half-life is 40 hours at pH 6.5 and 1.4 hours at pH 8.5 and 20 °C; its half-life decreases further as temperature increases.
The enzyme alkaline phosphatase (ALP, alkaline phenyl phosphatase, also abbreviated PhoA) is a phosphatase with the physiological role of dephosphorylating compounds. The enzyme is found across a multitude of organisms, prokaryotes and eukaryotes alike, with the same general function, but in different structural forms suitable to the environment they function in. Alkaline phosphatase is found ...
The enzyme's activity towards native proteins is stimulated by denaturants such as SDS. In contrast, when measured using peptide substrates, denaturants inhibit the enzyme. The reason for this result is that the denaturing agents unfold the protein substrates and make them more accessible to the protease.