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In biochemistry, denaturation is a process in which proteins or nucleic acids lose folded structure present in their native state due to various factors, including application of some external stress or compound, such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), agitation and radiation, or heat. [3]
Most enzymes are sensitive to pH and have specific ranges of activity. All have an optimum pH. The pH can stop enzyme activity by denaturating (altering) the three-dimensional shape of the enzyme by breaking ionic, and hydrogen bonds. Most enzymes function between a pH of 6 and 8; however pepsin in the stomach works best at a pH of 2 and ...
Many therapeutic drugs and poisons are enzyme inhibitors. An enzyme's activity decreases markedly outside its optimal temperature and pH, and many enzymes are (permanently) denatured when exposed to excessive heat, losing their structure and catalytic properties. Some enzymes are used commercially, for example, in the synthesis of antibiotics.
Pepsin may be inhibited by high pH (see Activity and stability) or by inhibitor compounds. Pepstatin is a low molecular weight compound and potently inhibitor specific for acid proteases with an inhibitory dissociation constant (Ki) of about 10 −10 M for pepsin.
It contains four iron-containing heme groups that allow the enzyme to react with hydrogen peroxide. The optimum pH for human catalase is approximately 7, [8] and has a fairly broad maximum: the rate of reaction does not change appreciably between pH 6.8 and 7.5. [9] The pH optimum for other catalases varies between 4 and 11 depending on the ...
Intracellular pH (pH i) is the measure of the acidity or basicity (i.e., pH) of intracellular fluid. The pH i plays a critical role in membrane transport and other intracellular processes. In an environment with the improper pH i , biological cells may have compromised function.
Further addition of substrate would not increase the rate, and the enzyme is said to be saturated. The Michaelis constant is not affected by the concentration or purity of an enzyme. [16] Its value depends both on the identity of the enzyme and that of the substrate, as well as conditions such as temperature and pH.
Acid phosphatase (EC 3.1.3.2, systematic name phosphate-monoester phosphohydrolase (acid optimum)) is an enzyme that frees attached phosphoryl groups from other molecules during digestion. It can be further classified as a phosphomonoesterase .