Noadswood Science, 2012

EnzymesTo understand how enzymes work

Thursday, May 4, 2023

EnzymesEnzymes are biological catalysts - catalysts are substances

that increase the rate of chemical reactions without being used up

Enzymes are specifically proteins that are folded into complex shapes that allow smaller molecules to fit into them – the place where these substrate molecules fit is called the active site

Enzymes If the shape of the enzyme changes, its active site may no longer

work – the enzyme has been denatured

They can be denatured by high temperatures or extremes of pH

*It is wrong to say the enzyme has been killed – although enzymes are made by living things, they are proteins, and not alive

Enzyme ImportanceEnzymes are important catalysts in a variety of reactions

within the body, including respiration and digestion, protein synthesis and photosynthesis

They are also important within industry, such as developing biological detergents and sports drinks…

Trypsin ExperimentTrypsin is an enzyme which breaks down protein

If Trypsin is added to milk it will break down the milk, turning it from cloudy to translucent

You need to carry out an experiment to find out how the temperature of the Tryspin affects how quickly the milk is broken down

You will have 3 boiling tubes of milk

To each you will add some Tryspin which is at different temperatures

You need to time how long the solution went from being cloudy to translucent

Tryspin ExperimentTake 3 boiling tubes, and fill them each with 10ml of milk –

place them in a rack

Add 10ml of cold Trypsin to one boiling tube with milk in, and begin the timer – time how long it takes for the solution to become transparent

Repeat this with the second boiling tube, but this time add 10ml warm Trypsin

Repeat this with the third boiling tube, but this time add 10ml boiling Trypsin

Record all your results

ExplanationExplain why when the Trypsin was cold the solution turned clear

slowly

Explain why when the Trypsin was warm the solution turned clear quickly

Explain why boiling the Trypsin caused the solution to remain cloudy

TemperatureAs the temperature increases, so does the rate of reaction

Very high temperatures denature enzymes

The graph shows the typical change in an enzyme's activity with increasing temperature

The enzyme activity gradually increases with temperature until around 37°C

As the temperature continues to rise, the rate of reaction falls rapidly, as heat energy denatures the enzyme

Summary Enzymes