Feedforward activation is a process used in
metabolic pathways by which an early product in the pathway activates (or catalyzes) future reactions. The concentration of an earlier reactant not involved in the continual chemical reactions of the pathway will help to catalyze final reactions down the pathway. This process occurs in either
linear pathways or
branched pathways, however, it will not be found in conjunction with its opposite twin process,
feedback inhibition. In fact, the two are sometimes found counteracting each other in two pathways performing opposite functions.
The reactant which serves as the feedforward activator is intrinsically linked to the final product it helps to catalyze. The whole process keeps a pathway from going too fast since any activating reactant incorporated into the pathway can no longer feed forward. High concentrations of the reactant are needed to really send the pathway along during metabolism.
This is an ASCII diagram of the process, with each letter representing a compound synthesized or deconstructed as part of a pathway:
A --> B --> C --> D --> P
| .oOo.
|______________|