What is end-product inhibition?

End-product inhibition is a form of negative feedback for regulation of metabolic pathways, where the final product in a series of reactions causes an inhibitory effect in an earlier step in the sequence.

End product inhibition (as it self explains) is a phenomenon where the end product of an enzymatic reaction inhibits the initial reaction or enzyme that led to the formation of the end product. For example, thyroid stimulating hormone (TSH) stimulates the production of thyroid hormone T4 in the body whereas increase in T4 (which is the end product) “inhibits” the secretion of TSH.

End product inhibition is important in regulating metabolic pathways. The final product often acts as a regulator of the pathway.

When the amount of end product is high, it binds non-competitively to an enzyme earlier in the pathway, blocking further production of itself.

When the amount of end product falls, inhibition ends and the pathway restarts. This is also an example of negative feedback