Enzyme Kinetics — Michaelis-Menten

At substrate concentration equal to Km, what percentage of enzyme active sites are occupied by substrate molecules?

A biochemistry student is comparing two enzyme inhibitors used in drug design. Inhibitor A increases the apparent Km while leaving Vmax unchanged. Inhibitor B decreases Vmax while leaving Km unchanged. Which kinetic feature best distinguishes competitive inhibition from non-competitive inhibition?

Under what condition does the Michaelis-Menten equation simplify to first-order kinetics with respect to substrate concentration?

A 28-year-old woman with a family history of hereditary fructose intolerance presents with severe hypoglycemia, hepatomegaly, and lactic acidosis after consuming a fruit-based meal. Genetic testing reveals a deficiency in aldolase B. In vitro studies of her hepatic tissue show that the enzyme fructokinase (which catalyzes the first step of fructose metabolism) exhibits normal Vmax but a markedly reduced Km for fructose. Blood fructose levels are significantly elevated (12 mM; normal <1 mM). Based on Michaelis-Menten kinetics, which statement best explains why this patient develops severe hypoglycemia despite high fructose availability?

A pharmaceutical company is developing two protease inhibitors for COVID-19. Drug X shows a Lineweaver-Burk plot with lines that intersect on the y-axis at varying substrate concentrations. Drug Y shows lines that intersect on the x-axis. Which kinetic parameter best distinguishes the mechanism of action of Drug X from Drug Y?