Investigation into the factors that effect rennin
Uploaded by Sxyclr on Jan 17, 2006
RESEARCH
I know that Rennin is an enzyme, so before conducting this experiment I am first going to do some research into enzymes and their effects.
1. Enzymes
Enzymes are large globular molecules of which the vast majority are protein in nature, though some, known as 'ribozymes' are made of RNA. Enzymes have catalytic properties; in other words, they alter the rate of reaction without themselves undergoing a permanent change.
Most chemical reactions require an initial input of energy, called activation energy, to enable them to occur. Enzymes reduce the need for activation energy and so allow reactions to take place more readily and at lower temperatures than would otherwise be necessary. This can be seen in the graphs.
2. Enzyme Action
Enzymes, as biological catalysts, can be used in both anabolism (the build up of simple chemicals into complex ones) and catabolism (the breakdown of complex chemicals into simpler ones), although the latter is more common especially in the animal digestive system.
As shown in the next diagram it is thought that the substrate molecules fit precisely into the enzyme molecules. This theory is referred to as the lock and key mechanism. However, in practice, it is likely that the enzyme itself to some extent is the substrate.
The part of the enzyme molecule into which the substrate fits is called the active site. The configuration of the enzyme is due to ionic bonding, hydrogen bonding, disulphide bridges and hydrophobic interactions.
3. Specificity
The substrate molecule makes a precise fit into the active site and though the enzyme may be flexible up to a point, the number of molecules which can fit into the active site is very small - in fact it is often limited to just one type. Therefore enzymes are specific to one type of reaction.
4. Reversibility
Enzymes can catalyse the forward and reverse reactions equally.
5. Temperature
As temperature increases, the molecules, according to the 'Kinetic Theory' move faster, due to increased energy. Therefore, the enzyme and substrate molecules will meet more often and the rate at which the product is formed will increase. However, as the temperature continues to rise the hydrogen and ionic bonds, which hold the enzyme in shape, break and the active site will no longer accommodate the substrate. The enzyme is then said to be denatured - this cannot be reversed.
6. pH
Efficient functioning of an enzyme depends upon the shape of its active site. This shape is determined, in part, by...