A quick introduction to enzymes
Enzymes are biological catalysts - they speed up reactions without being themselves used up.
Without enzymes, all the reactions that are necessary for our body wouldn't happen at a fast enough rate to keep us alive. As an example, without enzymes, the amino acids that are needed for the genetic coding of DNA and RNA.
Enzymes are catalysts but, as they are used in the body, they have to be very specific and as such, each type of enzyme can only carry out its job with substrates (what it reacts with) that are of the correct shape - you can think about it like a lock-and-key, each key is specific to its lock just like each substrate being specific to its enzyme.
Without enzymes, all the reactions that are necessary for our body wouldn't happen at a fast enough rate to keep us alive. As an example, without enzymes, the amino acids that are needed for the genetic coding of DNA and RNA.
Enzymes are catalysts but, as they are used in the body, they have to be very specific and as such, each type of enzyme can only carry out its job with substrates (what it reacts with) that are of the correct shape - you can think about it like a lock-and-key, each key is specific to its lock just like each substrate being specific to its enzyme.
At a closer look, Enzymes are proteins and as such are not living nor dead. They catalyse reactions when substrates collide with a certain amount of energy into their active site. If the substrate fits the active site, the enzyme will either break apart a large substrate into 2+ products or join 2+ smaller substrates into one bigger product. As enzymes are not living, they cannot die but they something can happen to them that stops them working. Enzymes are designed to work best at their optimum temperature (body temperature) and temperature changes can actually affect how well enzymes work and, if it is brought to the extremes, they will denature.
Enzymes can be thought about like a lock and key, each enzyme only acts on a particular type of substrate, but things can happen to change this and once an enzyme denatures, it is useless. (and is destroyed, but this is unnecessary information at GCSE level.) The way denaturing works is that high temperatures (50 degrees C or higher usually) or very acidic or alkaline (depending on the enzyme) will change the structure of the active site or lock meaning the enzyme's key or substrate will no no longer match the active site or lock of the enzyme. The reason why we say depending on the enzyme is because some enzymes, like some proteases work in the stomach where is is pH 1 or 2 so low pH is fine with them but alkaline pHs will cause denaturation while for something like amylase which works in the mouth, pH 7 is its optimum and so alkaline or acid pHs will cause the denaturationof those specific enzymes.
What types of enzymes are there, where are they located and what do they work on?
There are 4 main groups of enzymes that you need to know for GCSE and they are:
1. Amylase - found in the mouth, pancreas and the small intestine, mainly the duodenum, this enzyme works on starch to turn it into maltose. Its optimum pH is 7.
2. Maltase - found in the small intestine, mainly the duodenum and pancreas, maltase works to turn maltose into glucose to be used in respiration. Its optimum pH is 7.
3. Lipases - found in the pancreas and the small intestine, mainly the duodenum, these enzymes works to turn lipids of fats into fatty acids and glycerol, which are then absorbed by lacteals in the villi. Their optimum pH varies.
4. Proteases - found in the stomach, pancreas and small intestine, mailny the duodenum, this group of enzymes works to turn proteins into their amino acid forms. Their optimum pH varies.
1. Amylase - found in the mouth, pancreas and the small intestine, mainly the duodenum, this enzyme works on starch to turn it into maltose. Its optimum pH is 7.
2. Maltase - found in the small intestine, mainly the duodenum and pancreas, maltase works to turn maltose into glucose to be used in respiration. Its optimum pH is 7.
3. Lipases - found in the pancreas and the small intestine, mainly the duodenum, these enzymes works to turn lipids of fats into fatty acids and glycerol, which are then absorbed by lacteals in the villi. Their optimum pH varies.
4. Proteases - found in the stomach, pancreas and small intestine, mailny the duodenum, this group of enzymes works to turn proteins into their amino acid forms. Their optimum pH varies.
