Method for regulating enzyme activities by noble gases

A method for using an enzyme to act on a substrate therefor in a liquid medium, which enzyme activity is regulated by causing an atmosphere surrounding said liquid medium to undergo a transition from being an enzyme activity inhibitor to an enzyme activity enhancer or vice versa, relative to when air is used as said atmosphere, by a change in temperature, which method comprises contacting at least one enzyme selected from the group consisting of oxidoreductases, lyases, isomerases and ligases, with the substrate therefor in said liquid medium, and during at least part of said contacting, contacting said at least one enzyme with an amount to so regulate said enzyme activity of said atmosphere, which consists essentially of argon, neon, xenon, krypton or a mixture thereof, at a temperature effective to cause said transition, and at a pressure of up to about 3 atmospheres.