Enzyme regulation (article) | Khan Academy

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• As these cellular demands and conditions changes, so do the amounts and functionality of different enzymes.

• factors that can affect or control enzyme activity. These include pH and temperature (discussed in the active site article), as well as:

• Enzyme activity may be turned "up" or "down" by activator and inhibitor molecules that bind specifically to the enzyme.

• Regulatory molecules

• Cofactors

• Many enzymes are only active when bound to non-protein helper molecules known as cofactors.

• Storing enzymes in specific compartments can keep them from doing damage or provide the right conditions for activity.

• Compartmentalization

• Feedback inhibition

• Key metabolic enzymes are often inhibited by the end product of the pathway they control (feedback inhibition).

• an activator or inhibitor's binding is reversible,

• reversible inhibitor. 1 1

• It blocks activity of a viral enzyme that helps the virus make more copies of itself

• That is, only the inhibitor or the substrate can be bound at a given moment.

• Instead, it attaches at another site and blocks the enzyme from doing its job.

• it will decrease reaction rate when there's not much substrate, but can be "out-competed" by lots of substrate

• binds to an enzyme someplace other than the active site

• allosterically regulated have a set of unique properties that set them apart

• Allosteric enzymes typically have multiple active sites located on different protein subunits.

• Also, in a process called cooperativity, the substrate itself can serve as an allosteric activator: when it binds to one active site, the activity of the other active sites goes up. 3 3 cubed This is considered allosteric regulation because the substrate affects active sites far from its binding site.