Control of enzyme activity Flashcards
two methods of controlling enzyme activity
allostery
post translational modifications
definition of allosteric regulation
activity of the enzyme is affected by the binding of an EFFECTOR molecule at the enzyme’s allosteric site (not the active site)
What is an allosteric activator?
a molecule that enhances the enzyme’s activity
What is an allosteric inhibitor?
a molecule that decreases an enzyme’s activity
allostery is often used as part of
feedback inhibition
eg. the first step in the pathway is regulated by the product
converting threonine to isoleucine: isoleucine is a negative regulator of threonine dehydratase
one and two component systems use
allostery and post translational modifications!
conformation of DNA binding sites can be changed by effectors
phosphotransfer affects kinase and regulator
post translational modifications are
covalent modifications to the enzyme after it has been translated
can activate or repress the enzyme
regulatory mods are usually reversible!
examples of post translational modifications
phosphorylation, methylation, adenylylation, uridylylation, acetylation
Post translational phosphorylations can occur on
histidine, aspartate, glutamate, serine, threonine and tyrosine
