Inhibitors therefore slow the rate of reaction. .
vi) Enzyme Concentration - Provided there is an excess substrate, an increase in enzyme concentration will lead to a corresponding increase in rate of reaction. Where the substrate is in short supply (i.e. it is limiting) an increase in enzyme concentration has no effect.
Observations and Measurements.
In the boiling tubes it was clear that a reaction was taking place by the observation of bubbles of oxygen gas being released creating a 'fizzing' in the boiling tubes.
In order to decide how varying the enzyme concentration affected the decomposition of hydrogen peroxide, the rate of reaction was measured. To do this accurately, the time taken for a specific quantity of oxygen gas (a product of the reaction) to be released was determined. This was achieved by observing the time taken for the manometer fluid to travel between the two marked fixed points as it was forced through the manometer by the rising gas. This was an accurate measure of how the enzyme concentration influenced the breakdown of hydrogen peroxide, as the quantity and speed of gas produced is dependant on the rate of reaction. .
All measurements were taken so that the stopwatch was started once the rubber tubing was sealed and the stopwatch stopped once the manometer fluid had reached the base of the highest marked point. To judge accurately, the point at which the fluid reached the marked line, it was examined at eye level and the measurement taken when the bottom of the meniscus was lined up to the mark. This was the same for every reading.
Safety .
Laboratory coats were worn during the investigation to prevent chemicals from spoiling clothes. Care was also taken whilst handling the chemicals as hydrogen peroxide is corrosive and the manometer fluid is permanently staining. Whilst using the razor blades, care was also taken to hold them by the handle and not the blade to prevent an accident occurring.
