Enzyme

Enzymes are types of proteins that, in small quantities, increase the rate of biological reactions without being used-up in the reactions themselves.

That is: Enzymes can act as catalysts.

Enzymes form within living cells and may act either within the cell or outside it.

Many enzymes are unstable and are easily de-activated, e.g. by heat or by other chemicals.

Certain enzymes are essential for normal functioning and development of the human body. Failure in the production or activity of even a single enzyme can lead to serious problems such as medical disorders.

How do enzymes act as catalysts ?

Particular enzymes catalyse specific reactions.

There are many different enzymes that assist in many of the huge range of different biochemical reactions. Even when considering the specific enzyme that could help with a particular reaction, each enzyme needs certain conditions in order to act as a catalyst with the maximum possible efficiency - for that particular enzyme facilitating that particular reaction.

Such conditions may include:

• A particular temperature range,
• A particular range of pH values,
• The presence of specific other enzymes (called "co-enzymes"),
• The lack of particular inhibitors (i.e. substances that reduce or prevent that particular reaction).

Names of specific enzymes:

The names of many enzymes end with the suffix "-ase". They are generally named according to either the substrate on which they act (e.g. lactase), or according to the type of reaction they catalyse (e.g. hydrolase).