DEHYDROGENIZATION
Reaction of biological oxidation without participation of oxygen is called dehydrogenization. A compound becomes oxidized when each of its molecules loses 2 atoms of hydrogen. These atoms cannot be merely eliminated. They must be transferred to other molecules, which becomes reduced as the result of that. In this type of reactions, like in all oxidation-reduction reactions, one molecule always becomes oxidized, and the other one becomes reduced. The role of the acceptors of hydrogen is played by molecules of several different types. They are comparatively small organic molecules (their molecular weight is about 500 dalton). They join specific proteins and form active enzymes. The protein component of such compound does not possess enzymatic activity by itself. Such activity appears only due to connection to a low-molecular "partner". Small molecules, on which the activity of an enzyme depends, are known as co-enzymes.