An enzyme can catalyze the conversion of two different substrates to two different products. Both reactions have the same Vmax (100 (u)moles/min) but different values for Km. In test tube #1, 10 (u)M substrate #1 is incubated with enzyme and product is formed at a rate of 10 (u)moles/min. In a separate test tube, 10 (u)M substrate #2 is incubated with enzyme and product is formed at a rate of 1.0 (u)moles/minute. Both substrates are present at equal concentrations. We can conclude that, approximately:

KEY: (u) refers to the unit micro

A. Km for substrate 1 = Km for substrate 2
B. Km for substrate 1 = 10 X Km for substrate 2
C. Km for substrate 1 = 0.1 X Km for substrate 2
D. The reaction is independent of substrate concentration when [S]<< E. None of these approximations are valid under these conditions.