Upgrade to remove ads
Terms in this set (20)
Kinetic controls on enzyme activity
Interactions with other proteins
Regulate induction and repression of protein/enzyme synthesis
Regulate protein turnover rate
Rate slows as product accumulates (product inhibition)
Rate depends on substrate availability
Law of mass action controls many near equilibrium reactions
Where do allosteric enzymes bind?
Outside of the substrate site
Are often metabolites that indicate overall metabolic state
Can be feed-forward activators or feedback inhibitors
What is the kinetic curve like for allosteric enzymes?
Sigmoidal (S shaped)
Allosteric enzymes exhibit...
Cooperativity in substrate binding
Need less substrate to get maximal activity, shifts curve to the left
Need more substrate to get maximal activity, shift curve to the right
An equilibrium exists between two distinct conformations or states
- Binding of substrates and effectors shifts the equilibrium between the states
Binding of substrates or effectors induces sequential conformation changes in adjacent subunits that influence the affinity for binding additional S
Reversible regulation by covalent modification
Phosphorylation and dephosphorylation
Which residues can be phosphorylated?
Serine, threonine and tyrosine (all have OH)
How does phosphorylation induce enzyme modification?
Free energy of phosphorylation is large (-50 kJ/mol), shifting enzyme in conformational state
Using ATP also links cellular energy status
How are protein kinases controlled?
Kinases target specific sequences (consensus) in their substrate
Other proteins can mimic these consensus sequences and bind, inactivating the kinase
What is the consensus sequence for protein kinase A?
Transfer of acetyl group from acetyl-CoA to Lysine epsilon amino group
Precursors of proteolytic enzymes that are irreversibly activated
THIS SET IS OFTEN IN FOLDERS WITH...
Amino Acids - One letter codes
Amino Acids - Structure, full name, & ac…
YOU MIGHT ALSO LIKE...
biochem ch 15
Module 3 Worksheet
cell bio lecture 5
OTHER SETS BY THIS CREATOR
DNA Repair Pathways
Protein Targeting Sequences
Cytoskeleton & Diseases