Chapter 8.5.3 (Exam 2) Allostery Flashcards
Enzyme Activities Can Be Regulated
Describe the reaction rate in allosteric enzymes.
very sensitive to substrate concentration (over a certain range)
very sensitive to low concentrations of inhibitors
What is the commitment step in metabolic pathways?
The first reaction, the other reactions happen in sequence
What happens in a metabolic pathway if the cell no longer requires the product?
Feedback inhibition: The final product usually acts as a noncompetitive inhibitor of the first enzyme, which shuts down the pathway
What is the function of reverse phosphorylation?
Regulating enzymes: enzymes can be activated when protein kinase adds a phosphate group and deactivated by protein phosphatase removing a phosphate group
What is the function of a protein kinase in enzyme phosphorylation?
Enzymes can be activated when protein kinase adds a phosphate group
What is the function of a protein phosphatase in enzyme regulation?
Enzymes can be deactivated by protein phosphatase removing a phosphate group
Why is enzyme function dependent on pH?
Differing pH can ionize or deionize functional groups, changing enzyme shape and the different substrate it may fit
E.g. at low pH (high H+) —COO– may react with H+ to form —COOH which is no longer charged; this affects folding and thus enzyme function.
Why does every enzyme have an optimal temperature?
At high temperatures, noncovalent bonds begin to break, breaking down tertiary structure and causing denaturation
Which bonds are more present in enzymes that are adapted to warmer temperatures?
Covalent bonds because they are stronger
Why does the human body fight infections with fevers?
Most human enzymes are stable at high temperatures compared to bacterial enzymes
