Katal

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Katal

The katal (symbol: kat) is the SI

Si, si, or SI may refer to :...
unit of catalytic

Catalysis

Catalysis is the process in which the reaction rate of a chemical reaction is either increased or decreased by means of a chemical substance known as a catalyst....
activity. It is a derived SI

Si, si, or SI may refer to :...
unit for expressing quantity values of catalytic activity of enzyme

Enzyme

Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
s and other catalysts. Its use is recommended by the General Conference on Weights and Measures
General Conference on Weights and Measures

The General Conference on Weights and Measures is the English name of the Conf?rence g?n?rale des poids et mesures . It is one of the three organizations established to maintain the International System of Units under the terms of the Convention du M?tre of 1875....
and other international organizations. It replaces the non-SI enzyme unit
Enzyme unit

The enzyme unit is a unit of measurement for the amount of a particular enzyme.One U is defined as that amount of the enzyme that catalysis the conversion of 1 micro mole of substrate per minute....
. Enzyme units are, however, still more commonly used than the katal in practice at present, especially in biochemistry

Biochemistry

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Encyclopedia

The katal (symbol: kat) is the SI

Si, si, or SI may refer to :...
unit of catalytic

Catalysis

Si, si, or SI may refer to :...
unit for expressing quantity values of catalytic activity of enzyme

Enzyme

Biochemistry

Biochemistry is the study of the chemistry processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules....
.

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

Trypsin

Trypsin is a serine protease found in the digestive system, where it breaks down proteins. Trypsin predominantly cleaves peptide chains at the carboxyl side of the amino acids lysine and arginine, except when either is followed by proline....
, for example, is that amount of trypsin which breaks a mole

Mole (unit)

The mole is a Units of measurement of amount of substance: it is an SI base unit, and one of the few units used to measure this physical quantity....
of peptide

Peptide

Peptides are short polymers formed from the linking, in a defined order, of a-amino acids. The link between one amino acid residue and the next is known as an amide chemical bond or a peptide bond....
bonds per second under specified conditions.

Definition

1 kat = 1 mol

Mole (unit)

The mole is a Units of measurement of amount of substance: it is an SI base unit, and one of the few units used to measure this physical quantity....
/s

Second

The second , sometimes abbreviated sec., is the name of a units of measurement of time, and is the International System of Units SI base unit of time....

SI multiples

Origin

The name katal has been used for decades and it became an official SI unit in 1999.

External links

Unit "katal" for catalytic activity (IUPAC Technical Report) Pure Appl. Chem. Vol. 73, No. 6, pp. 927-931 (2001)