Find kcat for a reaction in which Vmax is 4 x 10⁻⁴ mol•min-1 and the reaction mixture contains one microgram of enzyme (the molecular weight of the enzyme is 200,000 D).
a. 2 x 10⁻¹ min⁻¹
b. 2 x 10⁻¹⁴ min⁻¹
c. 8 x 10⁹ min⁻¹
d. 8 x 10⁷ min⁻¹
e. 4 x 10⁸ min⁻¹