The katal (symbol: kat) is the SI unit of catalytic activity. It is a derived SI unit for expressing quantity values of catalytic activity of enzymes and other catalysts. Its use is recommended by the General Conference on Weights and Measures and other international organizations. It replaces the non-SI enzyme unit. Enzyme units are, however, still more commonly used than the katal in practice at present, especially in biochemistry.

The katal is not used to express the rate of a reaction; that is expressed in units of concentration per second (or moles per liter per second). Rather, it is used to express catalytic activity which is a property of the catalyst. The katal is invariant of the measurement procedure, but the numerical quantity value is not and depends on the experimental conditions. Therefore, in order to define the quantity of a catalyst, the rate of conversion of a defined chemical reaction has to be specified, preferably of the first order, under strictly controlled conditions. One katal of trypsin, for example, is that amount of trypsin which breaks a mole of peptide bonds per second under specified conditions.

Read more about KatalDefinition, SI Multiples, Origin

Other articles related to "katal":

Enzyme Assay - Enzyme Units - Enzyme Activity
... The SI unit is the katal, 1 katal = 1 mol s−1, but this is an excessively large unit ... Enzyme activity as given in katal generally refers to that of the assumed natural target substrate of the enzyme ...
Katal - Origin
... The name katal has been used for decades and it became an official SI unit in 1999. ...
Enzyme Unit
... unit, the enzyme unit is discouraged in favour of the katal, the unit recommended by the General Conference on Weights and Measures in 1978 and officially adopted in 1999 ... One katal is the amount of enzyme that converts 1 mole of substrate per second, so 1 U = 1/60 micro katal = 16.67 nano katal ...