Original sentence: (2002) Vol.48, pp.6, pp.73, No.927-931 (2001).Enzyme units are, however, still more commonly used than the katal in practice at present, especially in biochemistry.It replaces the non-SI enzyme unit.Its use is recommended by the General Conference on Weights and Measures and other international organizations.One katal of trypsin, for example, is that amount of trypsin which breaks a mole of peptide bonds per second under specified conditions.Rather, it is used to express catalytic activity which is a property of the catalyst.The Tortuous Road to the Adoption of katal for the Expression of Catalytic Activity by the General Conference on Weights and Measures (Clinical Chemistry.The katal is a derived SI unit for expressing quantity values of catalytic activity of enzymes and other catalysts.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.Unit "katal" for catalytic activity (IUPAC Technical Report) Pure Appl
Edited sentence: "Units" are more commonly used than the katal in practice at present, but their definition lacks coherence with the SI system.One katal of trypsin, for example, is that amount of trypsin which breaks a mole of peptide bonds per second.Rather, it is used to measure the quantity of a catalyst.The formal adoption of the katal is hoped to discourage the use of a non-SI unit called "unit", symbol "U", defined as micromoles per minute