Enzymes

What is Vmax

Vmax is the maximum rate of an enzymatic reaction when the enzyme is saturated with substrate. It represents the point at which adding more substrate will not increase the reaction rate.

What is Km

Km is the substrate concentration at which the reaction rate is half of Vmax. It reflects the affinity of the enzyme for its substrate.

What is the relationship between Km and enzyme-substrate affinity

Inversely related, as Km increases, enzyme-substrate affinity decreases

How are line-weaver burke plots read?

y-intercept is the inverse of Vmax, x-intercept is the negative inverse of Km. For both axes, closer to 0 is higher Vmax and Km

what is competitive enzyme inhibition

the inhibitor competes for the active site, can be overcome by increasing substrate concentration. This results in a higher Km (lower E-S affinity) without affecting Vmax.

what is non-competitive inhibition

inhibitor binds to allosteric site to change enzyme shape. Has equal affinity for enzyme and enzyme-substrate complex. Results in decreased Vmax and equal Km

what is uncompetitive inhibition

inhibitor only binds to the enzyme-substrate complex, preventing conversion to product. This decreases both Vmax and Km, produces a line-weaver burke plot with parallel lines

what is mixed inhibition

inhibitor binds to the allosteric site but either prefers the enzyme or the ES complex. Both lower Vmax. If preference for enzyme, Km increases, if preference for ES complex, Km decreases

what is an apoenzyme

an enzyme that does not have the cofactor it needs to work

what is a holoenzyme

an ezyme with the cofactor it requires to be active.

what is the difference between a cofactor and a coenzyme

a coenzyme is an organic molecule that helps the enzyme carry out its function, a cofactor is an inorganic molecule or ion that helps an enzyme carry out its function