How Does Temperature Affect Enzyme Activity
Enzymes are catalysts that increase the rate of chemical reactions organisms, allowing cells to break or build things instantly.
The structure of an enzyme is essential to its function. Enzymes are proteins, made up of 100-1000 amino acids bonded together in chains. These chains are folded/coiled into a unique 3-D structure that allows them to bind to a reactant, called a substrate at an active site. Enzymes are flexible, and therefore can change it’s shape to better accommodate its substrate; this is the induced fit model (D. Fraser, 50). When an enzyme binds to a substrate, it is called the enzyme substrate complex, where the substrate is then converted into different products. As an enzyme is not a part the reaction, it remains unchanged and therefore can continue binding to other substrate molecules, catalysing the same reaction repeatedly (D. Fraser, 51). …show more content…
There are many factors affecting enzyme activity.
Temperature affects enzymes in two different ways: by increasing the kinetic motion of molecules, changing the rate of collisions between them and the hydrogen bonds it’s 3D structure(D. Fraser, 55). There is a specific temperature for every enzyme where activity is maximized, and also where an enzyme becomes denatured. An enzyme becomes denatured when it is heated at extreme temperature; the excessive kinetic movement of the amino acid begins to break the hydrogen bonds holding its 3D structure together, typically around 70℃.
Another factor that can affect enzyme activity is substrate concentration. This is due to the amount of active sites available for an enzyme to bind at. When an enzyme concentration is constant but substrate concentration is increasing, a saturation point can be reached. This is where the enzymes are saturated with substrate (D. Fraser,
52).
Enzyme inhibitors also affect activity, by lowering the rate an enzyme can catalyze a reaction. There are different types of inhibition. Competitive inhibition is where a substance binds at an active site with a substrate in order to block an enzyme from binding there (D. Fraser, 53). Noncompetitive inhibition is where a molecule binds with an enzyme in order to prevent it from binding at an active site instead (D. Fraser, 53). Feedback inhibition is the regulation of a product from its specific reaction pathway; if there is an excess of product, molecules will bind with the enzymes to prevent it from binding at an active site (D. Fraser, 54).
When an organism uses molecular oxygen in a chemical reaction, many toxic byproducts are created including hydrogen peroxide, which can lead to oxidative stress (J. McDowall, PDB). Catalase is able to protect cells from this effect, by catalysing hydrogen peroxide into oxygen and water. In this experiment the substrate used is hydrogen peroxide and the enzyme used is catalase, found in beef liver.
The purpose of this lab was to determine the ideal substrate concentration and temperature to maximize enzyme activity of catalase. It is predicted that the ideal temperature will be at 40℃ and ideal substrate concentration at 5 mL of hydrogen peroxide.
The structure of an enzyme is essential to its function. Enzymes are proteins, made up of 100-1000 amino acids bonded together in chains. These chains are folded/coiled into a unique 3-D structure that allows them to bind to a reactant, called a substrate at an active site. Enzymes are flexible, and therefore can change it’s shape to better accommodate its substrate; this is the induced fit model (D. Fraser, 50). When an enzyme binds to a substrate, it is called the enzyme substrate complex, where the substrate is then converted into different products. As an enzyme is not a part the reaction, it remains unchanged and therefore can continue binding to other substrate molecules, catalysing the same reaction repeatedly (D. Fraser, 51). …show more content…
There are many factors affecting enzyme activity.
Temperature affects enzymes in two different ways: by increasing the kinetic motion of molecules, changing the rate of collisions between them and the hydrogen bonds it’s 3D structure(D. Fraser, 55). There is a specific temperature for every enzyme where activity is maximized, and also where an enzyme becomes denatured. An enzyme becomes denatured when it is heated at extreme temperature; the excessive kinetic movement of the amino acid begins to break the hydrogen bonds holding its 3D structure together, typically around 70℃.
Another factor that can affect enzyme activity is substrate concentration. This is due to the amount of active sites available for an enzyme to bind at. When an enzyme concentration is constant but substrate concentration is increasing, a saturation point can be reached. This is where the enzymes are saturated with substrate (D. Fraser,
52).
Enzyme inhibitors also affect activity, by lowering the rate an enzyme can catalyze a reaction. There are different types of inhibition. Competitive inhibition is where a substance binds at an active site with a substrate in order to block an enzyme from binding there (D. Fraser, 53). Noncompetitive inhibition is where a molecule binds with an enzyme in order to prevent it from binding at an active site instead (D. Fraser, 53). Feedback inhibition is the regulation of a product from its specific reaction pathway; if there is an excess of product, molecules will bind with the enzymes to prevent it from binding at an active site (D. Fraser, 54).
When an organism uses molecular oxygen in a chemical reaction, many toxic byproducts are created including hydrogen peroxide, which can lead to oxidative stress (J. McDowall, PDB). Catalase is able to protect cells from this effect, by catalysing hydrogen peroxide into oxygen and water. In this experiment the substrate used is hydrogen peroxide and the enzyme used is catalase, found in beef liver.
The purpose of this lab was to determine the ideal substrate concentration and temperature to maximize enzyme activity of catalase. It is predicted that the ideal temperature will be at 40℃ and ideal substrate concentration at 5 mL of hydrogen peroxide.