Applications of enzyme chemistry

• Enzymes are sometimes enhanced and supported in their activity by smaller molecules or metals ions. These reactants are called co-enzymes. We will not look further into the mechanisms of co-enzymes.
• Enzymes are not only used in our bodies to speed up reactions; they are also commercially used. One such case is ‘enzyme’-enriched detergents, which ‘eat away the dirt’.
• There are many other clever applications of enzymes in the chemical industry. For example, the soft centres of some hard boiled sweets contain a minute quantity of an enzyme. It slowly reacts to soften the sweet from the centre outwards and so causes the centre of the sweet to be soft and chewy.
  

How enzymes work

There have been many theories of the exact mechanism of the action of an enzyme because so little of it is needed to affect the rate of a reaction. Some enzymes can speed up a reaction by as much as 10–20 000 times. One explanation for the mechanism is as follows.

In a normal reaction the two reactants need to collide with each other many times for a reaction to occur. In each collision only a few of the molecules are in the correct orientation to actually react with their counterparts, so owing to the randomness of motion, the reaction can take some time. When an enzyme is used, the reactant fits onto the enzyme molecule in the correct specific orientation so that, when the other reactant comes close to the enzyme/reactant combination, it is immediately in the correct orientation and alignment for the two reactants to join up.

Enzymes

Enzymes are usually large long-chain protein molecules that act as a catalyst for chemical reactions in the body. A catalyst is a material that speeds up a chemical reaction but is itself unchanged at the end of the reaction. Very small amounts of catalysts and enzymes can affect large quantities of reactants. They can, however, be poisoned if the conditions are changed and become unfavourable, or an impurity is present. Enzymes, being proteins, like to work at a set and narrow range of temperatures, and if they are warmed above their working temperature they become inactive due to being de-natured.

Enzymes cannot perform reactions that would not normally take place, they simply speed them up. One of the key features of enzymes is their characteristic and specific shape. One enzyme does not work with another reaction because the reactant and enzyme interlock and this depends upon their mutual matching shapes.
Enzymes are usually specific to one type of reaction.