Over the course of three repeat days at the end of November, I ran a set of practical classes and gave a lecture aiming to provide Advanced Higher (otherwise known as S6) pupils with a snapshot of what it is like to be a student at the University of Aberdeen. These pupils come from schools in Aberdeen City, Aberdeenshire and many from further afield, such as Fort William, Inverness and Dornoch.
For these S6 Biology Days, as they are known, I took an existing lab class that we run in one of my second year biochemistry courses called Energy for Life, and split it into three parts to get the pupils testing three properties that are important in drug design. The pupils are provided with 28 different compounds, all based on household substances, such as herbs and spices, toiletries, over the counter medicines and cleaning products. This set of compounds is called a library, and is made from extracts of the various substances. The pupils were ultimately trying to find an inhibitor that could block the activity of an enzyme (molecular machines that all forms of life need to carry out the reactions needed for life, so they’re kind of important). The enzyme in question is called a phosphatase and is linked to certain diseases, so makes a good candidate for a drug target.
Step 1 for the pupils…check each compound to make sure it wasn’t too acidic or caustic, as a potential drug needs to be as close to the pH of the body as possible, which is about pH 7, or neutral. This is carried out using red cabbage juice, as it is an excellent indicator of different pH’s (you can try this at home by mixing red cabbage juice and vinegar, as it acidic – it should change colour).
Step 2…check each compound to make sure it doesn’t unfold proteins, as if this happens the proteins are rendered useless, so wouldn’t be a good property for a potential drug compound. This is achieved using a bright blue protein from spirulina algae (that you find in health food shops and smoothy bars). The pupils use it here as when it unfolds it loses its blue colour.
Step 3…check if the compounds can stop the phosphatase enzyme working. This test uses a chemical that the phosphatase enzyme can split apart, and when it does this the chemical turns yellow, so the more yellow colour created the more active the enzyme is.
So, overall, the pupils wanted to find a compound from the original 28 that was a neutral pH, did not unfold protein and could stop the target enzyme working. By the end of the day they had achieved this and from each day there were several different compounds that worked well, so a job well done by all in my opinion!
After these three tests, the added bonus is the pupils end up with a bright and colourful 96-well plate (used to carry out each test) and a really good experience as evidenced by their very positive feedback on the day.
In the middle of doing these three lab classes, they also listened to a one hour lecture, which I gave them a choice on. This year I gave them three options from lectures that I deliver in our Introduction to Medical Science first year course, and each set of pupils from each day chose a different lecture to keep me on my toes! Day 1 chose how an Aberdeen Professor was instrumental in the discovery of insulin, Day 2 chose what we have learnt from sequencing the human genome, and Day 3 chose how anatomy was revolutionised by the Reformation and other key discoveries to make it what it is today.
As ever the S6 Biology Days have been a great thing to be involved in and it was amazing to see people travelling such a long way to experience ‘a day in the life’ of an undergraduate student in Aberdeen!