Calculate the initial reaction velocity for an enzyme with Vmax of 150 µmol/min, Km of 15 mM, and substrate concentration of 10 mM.

• A. 45 µmol/min.
• B. 90 µmol/min.
• C. 75 µmol/min.
• D. 60 µmol/min.

Answer: (D)