In: Chemistry
Explain what Vmax and Km describe
Vmax is the reaction rate when the enzyme is fully saturated by substrate, indicating that all the binding sites are being constantly reoccupied.
Km is the concentration of substrate which permits the enzyme to achieve half Vmax.
Vmax : if concentration of substrate is incresed, more and more enzyme molecules are working. At half maximal velocity 50% enzymes are attached to the substrate. As more substrate is added, all enzyme molecule are saturated(utilized). Further increase in substrate cannot any effect in reaction velocity. This maximum velocity obtained is called Vmax.
Km : km is a value of substrate concentration at half maximal velocity.
It denotes that 50% of enzyme molecules are bound with substrate molecules at particular substrate concentration.
Km is independent of enzyme concentration.
If enzyme concentration if doubled, the Vmax will be double. But Km will remain exactly same.
Km is signature of enzyme. Km value is constant for an enzyme.
Km denotes the affinity of enzyme for substrate.. The lesser numerical value of Km, the affinity of enzyme for substrate is more.