Proteins

The enzyme- substrate complex only forms when the correct substrate molecule fits into the specific active site on an enzyme. The reaction is then catalysed, which leads to the enzyme- product complex before the products are released from the active site to complete the reaction.

Many enzymes end in –ase. This means you spot them amongst other words. Not all enzymes do however e.g. pepsin. Serum is blood plasma with a protein removed so it does not clot when it is stored.

An enzyme speed up a reaction by lowering the required activation energy. The activation energy is the amount of energy that must be reached before the reaction can start. This is often provided as heat energy. This means reactions can happen at a lower temperature than they might need to normally.

Proteins are polymers made up of amino acids, their monomer. 2 amino acids, their monomer. 2 amino acids joined together are called a dipeptide, a polypeptide is formed when more than 2 amino acids are joined together.

The biuret test is the test for proteins. If the results is negative it will remain blue, but if positive it will turn purple. The biuret test indicates the presence of peptide bonds.

The biuret test involves adding sodium hydroxide to your test solution, then adding dilute copper (II) sulphate. If protein is present a purple colour forms; if the protein is not present it will stay blue.

They bind to another site on the enzyme and this causes the active sites to change shape. This means that the substrate can no longer bind to the active site. Increasing the concentration of substrate will not make a difference as the inhibitor is not competing with it.

Competitive enzyme inhibitors work by binding to the active site as they have a similar shape to that of the substrate molecule. They are competitive so compete with the substrate for the active site. If all the active sites are full with the inhibitors then no substrate molecules will be able to bind, and so the reaction will stop.

The lock and key theory involves the substrate fitting into the active site. The induced fit theory states that binding…