Enzyme unit SI 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 The enzyme unit should not be confused with the international unit (IU); although it is true that both measure chemical activity and that for many enzymes 1 U = 1 IU (because for many enzymes the existing U was adopted as the newer IU), international units can be defined for the biologic activity of
Entropy entropy, have dimensions of energy divided by temperature, which has a unit of joules per kelvin (J K) in the International System of Units (or kg m s K in terms of base units). The entropy of a substance is usually given as an intensive property—either entropy per unit mass (SI unit: J K kg) or entropy per unit amount of substance (SI unit: J K mol). The French mathematician Lazare Carnot proposed in his 1803 paper "Fundamental Principles of Equilibrium and Movement" that in any machine the accelerations and shocks of the moving parts represent losses of "moment of