Explore how an accumulated product inhibits an earlier enzyme, regulating pathway output in examples such as isoleucine synthesis in IB Biology HL C1.1.16.
Feedback mechanisms are used in living organisms both to promote and respond to change.
Explain the regulation of metabolic pathways by end-product inhibition.
final product in pathway acts as an inhibitor/blocks (reaction)/slows (reaction);
first/early/earlier enzyme (in pathway is inhibited);
non-competitive / binds at allosteric site / causes active site to change;
production of end-product reduced/paused when there is an excess;
isoleucine inhibits enzyme using threonine as substrate at start of pathway to isoleucine;
negative feedback / production restarts when end-product used up/concentration drops;