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
Flick (physics) Flick (physics) In optical engineering and telecommunications engineering, the flick is a unit of spectral radiance. One flick corresponds to a spectral radiance of 1 watt per steradian per square centimeter of surface per micrometer of span in wavelength (W·sr·cm·μm). This is equivalent to 10 watts per steradian per cubic meter (W·sr·m). In practice, spectral radiance is typically measured in microflicks (10 flicks). One microflick is equivalent to 10 kilowatts per steradian per cubic meter (kW·sr·m). In radio astronomy, the unit flik was coined by a group at Lockheed in Palo Alto, California as a substitute for the SI derived