Enzymes: Lowering Barriers Flashcards
What does the Michaelis constant indicate?
the affinity of an enzyme for its substrate
What is done to determine the values of the constants Vmax and Km?
the relationship is converted to a linear equation
What plot is used to achieve this?
the Lineweaver-Burk plot
What is the exception to the plot making it easier to understand?
small errors in measured v are amplified by taking the reciprocal 1/v
Define competitive inhibition
-the inhibitor competes with the substrate for binding to the active site of the enzyme, leading to an increase in KM but no change in Vmax.
Define non-competitive inhibition
occurs when the inhibitor binds to a site other than the active site, decreasing Vmax without affecting KM.
What effect does uncompetitive inhibition have on Vmax and KM? Why?
both Vmax and KM are decreased, as the inhibitor binds only to the enzyme-substrate complex.
What are Prostaglandins?
hormones whose release causes inflammation
What do a number of drugs do to counter this?
they inhibit prostaglandin synthesis by inhibition of cyclooxygenase
Define Allosteric regulation
What does it result in?
involves the binding of a regulatory molecule at a site other than the active site, resulting in a conformational change that alters enzyme activity.
What is the relationship between Activation energy and reaction rates?
the reaction rate is inversely related to activation energy
(lower activation energies lead to faster reaction rates).
Why is KM important?
-insight into the substrate concentration needed to reach half of Vmax, reflecting the enzyme’s affinity for its substrate.
Define Covalent modification
the chemical alteration of enzyme structure, often by the addition or removal of a chemical group
-This can activate or deactivate the enzyme
What is the primary function of enzymes?
to catalyse biochemical reactions, facilitating the conversion of substrates into products while lowering activation energy.
