Editing Katal

{{Short description|SI derived unit of catalytic activity}}
{{for|the village|Katal, Iran}}
{{Cleanup|reason=article lacks important detail|date=February 2020}}
{{Infobox Unit
| name = katal
| standard = [[SI]]
| quantity = [[catalysis]]
| symbol = kat
| extralabel = In [[SI base unit]]s:
| extradata = [[mole (unit)|mol]]/[[second|s]]
}}
The '''katal''' (symbol: '''kat''') is a unit of the [[International System of Units]] (SI)<ref name=":1">{{cite journal |author=Nomenclature Committee of the International Union of Biochemistry (NC-IUB)|title=Units of Enzyme Activity|journal=European Journal of Biochemistry|volume=97 |pages=319–20 |year=1979 |doi = 10.1111/j.1432-1033.1979.tb13116.x |issue=2|doi-access=free}}</ref> used for [[Quantification (science)|quantifying]] the catalytic activity of [[enzyme]]s (that is, measuring  the [[enzyme assay#Enzyme activity|enzymatic activity]] level in [[enzyme catalysis]]) and other catalysts.<!-- Please do not link "catalyst"; it redirects to the already-linked catalysis. --> One katal is that [[catalytic activity]] that will raise the rate of conversion by one mole per second in a specified assay system.<ref name=":1" />

The unit "katal" is not attached to a specified measurement procedure or assay condition, but any given catalytic activity is: the value measured depends on experimental conditions that must be specified.<ref>{{Cite journal |last=Dybkær |first=R. |date=1979 |title=Approved recommendation (1978) quantities and units in clinical chemistry |url=https://www.sciencedirect.com/science/article/pii/0009898179900652 |journal=Clinica Chimica Acta |volume=96 |issue=1 |pages=157–183 |doi=10.1016/0009-8981(79)90065-2 |issn=0009-8981}}</ref><ref>{{Cite book |last=BIPM |title=Le Système international d’unités / The International System of Units (‘The SI Brochure’) |publisher=Bureau international des poids et mesures |year=2019 |isbn=978-92-822-2272-0 |edition=9e}}</ref> Therefore, to define the quantity of a catalyst in katals, the ''catalysed rate of conversion'' (the rate of conversion in presence of the catalyst minus the rate of spontaneous conversion) of a defined chemical reaction is measured in moles per second.<ref>{{Cite journal|date=2001|title=UNIT "KATAL" FOR CATALYTIC ACTIVITY (IUPAC Technical Report)|url=http://publications.iupac.org/pac/2001/pdf/7306x0927.pdf|journal=Pure and Applied Chemistry|volume=73|issue=6|pages=927–931|doi=10.1351/pac200173060927|last1=Dybkær|first1=René|s2cid=195819612 }}</ref> One katal of [[trypsin]], for example, is that amount of trypsin which breaks one mole of [[peptide]] bonds in one second under the associated specified conditions.{{clarify|date=February 2020}}

==Definition==
One katal refers to an amount of enzyme that gives a catalysed rate of conversion of one [[Mole (unit)|mole]] per [[second]].<ref>{{Cite journal|date=2014-05-01|title=Standards for Reporting Enzyme Data: The STRENDA Consortium: What it aims to do and why it should be helpful|journal=Perspectives in Science|language=en|volume=1|issue=1–6|pages=131–137|doi=10.1016/j.pisc.2014.02.012|issn=2213-0209|doi-access=free|last1=Tipton|first1=Keith F.|last2=Armstrong|first2=Richard N.|last3=Bakker|first3=Barbara M.|last4=Bairoch|first4=Amos|last5=Cornish-Bowden|first5=Athel|last6=Halling|first6=Peter J.|last7=Hofmeyr|first7=Jan-Hendrik|last8=Leyh|first8=Thomas S.|last9=Kettner|first9=Carsten|last10=Raushel|first10=Frank M.|last11=Rohwer|first11=Johann|last12=Schomburg|first12=Dietmar|last13=Steinbeck|first13=Christoph}}</ref><ref name=":0">{{Cite journal|last1=Baltierra-Trejo|first1=Eduardo|last2=Márquez-Benavides|first2=Liliana|last3=Sánchez-Yáñez|first3=Juan Manuel|date=2015-12-01|title=Inconsistencies and ambiguities in calculating enzyme activity: The case of laccase|url=http://www.sciencedirect.com/science/article/pii/S0167701215300853|journal=Journal of Microbiological Methods|language=en|volume=119|pages=126–131|doi=10.1016/j.mimet.2015.10.007|pmid=26459230|issn=0167-7012}}</ref> Because this is such a large unit for most enzymatic reactions, the nanokatal (nkat) is used in practice.<ref name=":0" />
:<math alt="katal equals mole per second">\text{kat}=\frac{\text{mol}}{\text{s}}</math>
The katal is not used to express the [[Reaction rate|rate of a reaction]]; that is expressed in units of concentration per second, as [[Mole (unit)|moles]] per [[liter]] per second. Rather, the katal is used to express catalytic activity, which is a property of the catalyst.

==SI multiples==
{{SI multiples|unit=katal|symbol=kat}}

== History ==
The [[General Conference on Weights and Measures]] and other international organizations recommend use of the katal.<ref>{{cite web|title=SI Brochure, Table 3: Coherent derived units in the SI with special names and symbols)|url=https://www.bipm.org/en/publications/si-brochure/table3.html|access-date=2019-05-13|publisher=Bureau international des poids et mesures (BIPM)|archive-date=2019-03-21|archive-url=https://web.archive.org/web/20190321011303/https://www.bipm.org/en/publications/si-brochure/table3.html|url-status=dead}}</ref> It replaces the non-SI [[enzyme unit]] of catalytic activity. The enzyme unit is still more commonly used than the katal,<ref name=":0" /> especially in [[biochemistry]].{{citation needed|date=September 2018}}<ref>{{Cite journal |last=Dybkaer |first=Rene |date=March 2002 |title=The tortuous road to the adoption of katal for the expression of catalytic activity by the General Conference on Weights and Measures |url=https://pubmed.ncbi.nlm.nih.gov/11861460/#full-view-affiliation-1 |journal=Clinical Chemistry |volume=48 |issue=3 |pages=586–90 |pmid=11861460 |via=National Library of Medicine, National Center for Biotechnology information}}</ref> The adoption of the katal has been slow.<ref name=":0" /><ref>{{Cite journal|last=Dybkaer|first=René|date=March 2002|title=The tortuous road to the adoption of katal for the expression of catalytic activity by the General Conference on Weights and Measures|journal=Clinical Chemistry|volume=48|issue=3|pages=586–590|doi=10.1093/clinchem/48.3.586|issn=0009-9147|pmid=11861460|doi-access=free}}</ref>

==Origin==

The name "katal" has been used for decades. The first proposal to make it an SI unit came in 1978,<ref name=":0" /><ref>{{Cite journal|date=1979|title=Units of Enzyme Activity Recommendations 1978|journal=European Journal of Biochemistry|publisher=Nomenclature Committee of the International Union of Biochemistry (NC-IUB)|volume=97|issue=2|pages=319–320|doi=10.1111/j.1432-1033.1979.tb13116.x|doi-access=free}}</ref> and it became an official SI unit in 1999.<ref name=":0" /><ref>{{Cite journal|date=2001|title=UNIT "KATAL" FOR CATALYTIC ACTIVITY (IUPAC Technical Report)|url=http://publications.iupac.org/pac/2001/pdf/7306x0927.pdf|journal=Pure and Applied Chemistry|volume=73|issue=6|pages=927–931|doi=10.1351/pac200173060927|last1=Dybkær|first1=René|s2cid=195819612 }}</ref><ref>{{Cite web|date=2016|title=Topic 20: Working with enzymes|url=http://www.ncbe.reading.ac.uk/SAFETY/PDF/EnzymeSafety.pdf|access-date=31 October 2020|publisher=The Association for Science Education}}</ref> The name comes from the [[Ancient Greek]] κατάλυσις (''katalysis''), meaning "dissolution";<ref name="AHD">{{Citation |author=Houghton Mifflin Harcourt |title=The American Heritage Dictionary of the English Language |publisher=Houghton Mifflin Harcourt |url=https://ahdictionary.com/word/search.html?q=catalysis}}</ref> the word "[[catalysis]]" itself is a Latinized form of the Greek word.<ref name="AHD"/><ref>{{cite web |last= Harper |first=Douglas |title=catalysis (n.) |url= https://www.etymonline.com/word/catalysis#etymonline_v_27786 |work=Etymonline |access-date=2019-04-03 }}</ref>

==References==
{{Reflist}}

==External links==
* Unit "katal" for catalytic activity (IUPAC Technical Report) ''Pure Appl. Chem.'' Vol. 73, No. 6, pp.&nbsp;927–931 (2001) [http://www.iupac.org/publications/pac/2001/7306/7306x0927.html]
* {{cite journal | title = The Tortuous Road to the Adoption of katal for the Expression of Catalytic Activity by the General Conference on Weights and Measures | author = René Dybkær | journal = Clinical Chemistry | date = 1 March 2002 | volume = 48 | issue = 3 | pages = 586–590 | doi = 10.1093/clinchem/48.3.586 | url = http://www.clinchem.org/cgi/content/full/48/3/586 | pmid = 11861460 | access-date = 8 December 2005 | archive-url = https://web.archive.org/web/20081006044014/http://www.clinchem.org/cgi/content/full/48/3/586 | archive-date = 6 October 2008 | url-status = dead | doi-access = free }}

{{SI units}}

[[Category:SI derived units]]
[[Category:Units of catalytic activity]]
[[Category:Units of chemical measurement]]