Katal 17140 222640579 2008-06-30T11:43:40Z AndersBot 6986250 robot Adding: [[be:Катал]] The '''katal''' (symbol: kat) is the [[SI]] unit of [[catalysis|catalytic]] activity.<ref>{{cite journal |author=Nomenclature Committee of the International Union of Biochemistry (NC-IUB) |title=Units of Enzyme Activity |journal=Eur. J. Biochem. |volume=97 |pages=319–20 |year=1979 |doi = 10.1111/j.1432-1033.1979.tb13116.x}}</ref> It is a derived [[SI]] unit for expressing quantity values of catalytic activity of [[enzyme]]s and other [[catalyst]]s. 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 moles 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 (unit)|mole]] of [[peptide]] bonds per second under specified conditions. ==Definition== <math> kat = mol/s </math> ==SI multiples== {{SI multiples|unit=katal|symbol=kat}} ==Origin== The name katal has been used for decades and it became an official SI unit in 1999. ==References== {{reflist}} ==External links== * Unit "katal" for catalytic activity (IUPAC Technical Report) ''Pure Appl. Chem.'' Vol. 73, No. 6, pp. 927-931 (2001) [http://www.iupac.org/publications/pac/2001/7306/7306x0927.html] * The Tortuous Road to the Adoption of katal for the Expression of Catalytic Activity by the General Conference on Weights and Measures (''Clinical Chemistry.'' (2002) Vol. 48, pp. 586-590. [http://www.clinchem.org/cgi/content/full/48/3/586] [[Category:SI derived units]] [[Category:Units of catalytic activity]] {{chem-stub}} [[be:Катал]] [[be-x-old:Катал]] [[bs:Katal]] [[ca:Katal]] [[da:Katal]] [[de:Katal]] [[es:Katal]] [[eo:Katalo]] [[fr:Katal]] [[ko:캐탈]] [[it:Katal]] [[nl:Katal]] [[ja:カタール (単位)]] [[no:Katal]] [[nn:Katal]] [[pl:Katal]] [[pt:Katal]] [[ru:Катал]] [[sk:Katal]] [[sr:Катал]] [[uk:Катал]]