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
Si River to the large amount of silt carried by the river, it left behind a high layer of mud in the lower reaches of the Si River’s former course. The philosopher Confucius is buried on the north bank of the Si River where it passes through Qufu City. The river was also traditionally regarded as a place where the Nine Cauldrons were lost. Si River The Si River is a river in Shandong Province, China. It also ran through the area of modern Jiangsu Province until floods in 1194. The Si rises in the southern foothills of the Mengshan Mountains (蒙山),