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The specific activity of an enzyme is another common unit. This is the activity of an enzyme per milligram of total protein (expressed in μmol min −1 mg −1).Specific activity gives a measurement of enzyme purity in the mixture.
The enzyme unit, or international unit for enzyme (symbol U, sometimes also IU) is a unit of enzyme's catalytic activity. [1]1 U (μmol/min) is defined as the amount of the enzyme that catalyzes the conversion of one micro mole of substrate per minute under the specified conditions of the assay method.
α-Amylase is an enzyme (EC 3.2.1.1; systematic name 4-α-D-glucan glucanohydrolase) that hydrolyses α bonds of large, α-linked polysaccharides, such as starch and glycogen, yielding shorter chains thereof, dextrins, and maltose, through the following biochemical process: [2]
The amount of starch break-down is directly proportionate to the alpha-amylase activity, meaning that the higher the activity of the alpha-amylase, the lower the viscosity will be. After 60 seconds of mixing, the stirrer is dropped from the top of the test tube, and the time it takes to reach the bottom is measured.
Different temperatures optimize the activity of alpha or beta amylase, resulting in different mixtures of fermentable and unfermentable sugars. In selecting mash temperature and grain-to-water ratio, a brewer can change the alcohol content, mouthfeel , aroma, and flavor of the finished beer.
In chemistry, the term "turnover number" has two distinct meanings.. In enzymology, the turnover number (k cat) is defined as the limiting number of chemical conversions of substrate molecules per second that a single active site will execute for a given enzyme concentration [E T] for enzymes with two or more active sites. [1]
The IC 50 of a drug can be determined by constructing a dose-response curve and examining the effect of different concentrations of antagonist on reversing agonist activity. IC 50 values can be calculated for a given antagonist by determining the concentration needed to inhibit half of the maximum biological response of the agonist. [ 4 ]
Degrees Lintner is an intensive unit, not an extensive one; it is independent of the quantity of malt used. While the measurement is applicable to any amylase, in general it refers to the combined α-amylase and β-amylase used in brewing. The term is also generalized to diastatic malt extracts and separately prepared brewing enzymes.