Activity of the Enzyme Catalase with Hydrogen Peroxide.

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Activity of the Enzyme Catalase with Hydrogen Peroxide

Background Information:

An enzyme (Catalase) is a biological catalyst. It can modify the rate of reaction without being changed itself. Enzymes are also globular proteins that have a three-dimensional specific shape; among with a pocket known as the active site, this has a precise shape to link with the exact substrate. Every enzyme are capable of converting one kind of substrate molecule into one kind of product molecule, which forms the enzyme-substrate complex. There are the minority factors that affect the rate of reaction that include:

  1. Temperature:

If the temperature was to increase so would the rate of reaction up to a decisive point, as the enzyme will start to denature; this usually occurs at temperatures around 50 to 60 Celsius. The rate of reaction increases because enzymes and substrate have more energy permitting them to move around more rapidly, resulting with more collisions and ensuring the enzyme-substrate complex. When the enzymes denature, the weak bonds that hold the tertiary structure of the enzyme together vibrate at an excessive rate, due to the kinetic energy, that they break as well as altering the shape of the active site to a degree that the substrate can no longer link to it.

  1. PH:

The formation of the enzyme-substrate complex relies on an exact complementary shape and charge. If there is a change in pH, it will corrupt the charges so that no enzyme-substrate complex can be formed. All enzymes have an optimum pH depending on where they are based, intracellular or extracellular.

  1. Substrate concentration:

The higher the concentration that faster the rate of reaction, which is until they are working as fast as they possible can. This increase in rate of reaction occurs because the more substrate there is the more chance there is of collisions resulting in the formation of enzyme-substrate complex. If the reaction is working fast as possible, the limiting factor is no longer the substrate but the enzyme concentration.

  1. Enzyme concentration:

This factor also enhances the rate of reaction because there are a greater number of active sites accessible for the enzyme-substrate complex to be formed.

  1. Inhibition:

The inhibitor decreases the rate of reaction because it alters the shape of the active site or either blocks the active site so that the enzyme cannot form the enzyme-substrate complex.

Hydrogen peroxide is formed by a product of chemical reactions in the living cells and is also toxic. If the cells do not deal with it instantaneously it could kill the cells themselves. Catalase is a very rapid reacting enzyme, which is formed in many living cells where it breaks down hydrogen peroxide to water and produces oxygen as a result. What's more is that one cell can deal with six million molecules of hydrogen peroxide in one minute.

Planning

Subsequent to the previous information, I have analysed it and taken it into consideration and I have come to the decision of conducting a practical where I will compare the rate at which oxygen is developed as a result of the breaking down of hydrogen peroxide, at different substrate concentrations. I will use the enzyme catalase of potatoes to see the affect that altering the substrate concentration has on the rate of reaction or the rate at which oxygen is evolved.

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I will now carry out a practical to investigate the effect of substrate concentration on the rate of activity of the enzyme catalase.

Below is a list of reasons why I have chosen to investigate substrate concentration instead of the other factors that were mentioned:

  • If I were to investigate the effect temperature has, I would find it difficult to keep the temperature constant.
  • I decided not to investigate pH because most enzymes only work on a narrow range of pH and keeping these constant would be a struggle and would result as inaccurate ...

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