L3 - enzyme concentration

• The greater the substrate concentration, the higher the rate of reaction. As the number of substrate molecules increases, the likelihood of enzyme-substrate complex formation increases
• The higher the enzyme concentration in a reaction mixture, the greater the number of active sites available and the greater the likelihood of enzyme substrate complex formation
• As long as there is sufficient substrate available, the initial rate of reaction increases linearly with enzyme concentration. If the amount of substrate is limited, at a certain point any further increase in enzyme concentration will not increase the reaction rate as the amount of substrate becomes a limiting factor
• If the enzyme concentration remains fixed but the amount of substrate is increased past a certain point, however, all available active sites eventually become saturated and any further increase in substrate concentration will not increase the reaction rate
• When the active sites of the enzymes are all full, any substrate molecules that are added have nowhere to bind in order to form an enzyme substrate complex. For this reason, in the graph below there is a linear increase in reaction rate as substrate is added, which then plateaus when all active sites become occupied