Question

A species of Shewanella bacteria contains an enzyme that catalyzes the dehalogenation of tetrachloroethene. The KM is 120 μM and the Vmax is 1.0 nmol·min–1·mg–1. What is the substrate concentration (µM) when the velocity is 0.75 nmol·min–1·mL–1?

Answer 1

Answer : The substrate concentration is, $360\mu M$

Explanation :

Using Michaelis–Menten equation :

$V=\frac{V_{max}\times [S]}{(K_m+[S])}$

Where,

$V_{max}$ = maximum rate velocity  = $1.0nmol/min.mg$

[S] = substrate concentration  = ?

Km = Michaelis–Menten constant  = $120\mu M$

V = reaction rate = $0.75nmol/min.mL$

Now put all the given values in the above formula, we get:

$0.75=\frac{1.0\times [S]}{(120+[S])}$

$[S]=360\mu M$

Thus, the substrate concentration is, $360\mu M$