THE EFFECT OF CHANGING ENZYME CONCENTRATION

The effect of changing enzyme concentration on the activity of the enzyme, catalase in liver cells



The effect of changing enzyme concentration on the activity of the enzyme, catalase in liver cells

The enzyme catalase speeds up the decomposition of Hydrogen Peroxide into water and oxygen as shown here, 2H2O2-------------------2H2O+O2. It is one of the fastest known enzymes and its turnover number is 6 million, which means the number of substrate molecules which one molecule of the enzyme turns to products per minute. This can be demonstrated by putting a piece of liver into a beaker of Hydrogen Peroxide, the fizzing shows a demonstration of the enzyme in action.

The Spearman's Rank Correlation Coefficient is used to discover the strength of a link between two sets of data. This example looks at the strength of the link between the price of a convenience item (a 50cl bottle of water) and distance from the Contemporary Art Museum in El Raval, Barcelona. Example: The hypothesis tested is that prices should decrease with distance from the key area of gentrification surrounding the Contemporary Art Museum. The line followed is Transect 2 in the map below, with continuous sampling of the price of a 50cl bottle water at every convenience store. The hypothesis might be written like this:

The price of a convenience item decreases as distance from the Contemporary Art Museum increases.

Spearman's Rank correlation coefficient

A correlation can easily be drawn as a scatter graph, but the most precise way to compare several pairs of data is to use a statistical test - this establishes whether the correlation is really significant or if it could have been the result of chance alone. Spearman's Rank correlation coefficient is a technique which can be used to summarise the strength and direction (negative or positive) of a relationship between two variables.

Aim

My aim is to examine how the concentration of the substrate hydrogen peroxide affects the enzyme catalase.

Investigation

I am going to investigate the effect of varying the substrate concentration on enzyme catalase. I am going to use 8 different concentrations and record the time taken to collect 20ml of gas in the gas syringe. I will repeat all the 8 concentrations twice so I can see if they match, spot out any anonymous results and also I can work out the average time it takes to produce 20ml of gas at the certain concentrations. I will vary the concentrations by increasing and decreasing the amounts of Hydrogen Peroxide and water. PLAN First of all I will ensure I have enough enzyme solution for the whole experiments so the enzyme solution is standardised. With the results I get I will try to work out the ½ Vmax. I will do this experiment at room temperature so the enzymes get enough kinetic energy to collide. I will need 80ml of the enzyme solution because I will use 5ml for all of the experiment and I will do 8 different concentrations and I ...