The enzyme is found in bacterial plasma membrane, in thylakoid membrane (chloroplast ATP synthase) and in inner mitochondrial membrane. The main function of the enzyme is ATP production.
In this case, the terminal velocity increases to about 320 km/h (200 mph or 90 m/s), which is almost the terminal velocity of the peregrine falcon diving down on its prey.
The frictional force of air depends on air pressure and density, shape of the falling body, etc. For example the terminal velocity of a sheet of paper or a balloon is much smaller than the terminal of a BB weighing the same amount. However, you can make an estimate for a human body. It is said, although I've never tried it myself, that the terminal velocity of an ordinary person falling in normal atmosphere at low altitudes is around V0 = 200 kilometers per hour ( ~ 120 mph).