enzyme kinetics question

[md4ever]

At a concentration of 5x10(-4) M substrate the velocity of the reaction catalyzed by the enzyme whose km is 5x10(-4) and v max is 30.

a)10
b)15
c)20
d)25
e)30




can anyone explain this.

[###]

.............

[md4ever]

thanks for the explanation

[md4ever]

of the substrate, what if the substrate conc was 5x10(-6),and vmax 20

[desai29]

USMLE also ask physics as well?

[hdu-o]

You do not even have to apply any equation, in the way the question was formulated, Just apply:
"the definition of Km -- Km is the substrate concentration at which the reaction velocity is half maximal."
Question:
"At a concentration of 5x10(-4) M substrate the velocity of the reaction catalyzed by the enzyme whose km is 5x10(-4) and v max is 30...."
Then:
The question condition is that the concentration of substrate is the same as the Km of the enzyme, so the velocity is half the maximal velocity: 30/2 = 15