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Enzymes And Their Role

What are Enzymes by Jane Thurnell-Read

A cell could theoretically produce a large range of different chemicals. The ones that are produced are determined by the presence of enzymes.

Enzymes are catalysts that speed specific reactions (usually millions or billions of times faster than without the enzyme). There are over 1000 different enzymes that we know about in the human body. There are likely to be many more that we do not know about. Enzymes are made from protein.

Many enzymes require the presence of an additional, non-protein, co-factors in order to be active. Zinc, manganese, potassium, sodium vitamins B1, B2 and nicotinamide are common co-factors.

The activity of enzymes is strongly affected by changes in acidity (pH) and temperature. Each enzyme works best at a certain pH and temperature. A raised body temperature disturbs the cellular machinery of the bacteria, but can also damage human cellular machinery.

Enzymes contain spaces (combining sites) that the material they work on (known as the substrate) fit into. The space has to be very specific to make sure only the right substrate will fit, so that enzymes work with only one or a small number of related substrates.

This fitting of the substrate into the enzyme has been likened to a key fitting in a lock, but the latest research suggests that the substrate does have an effect on the shape of the enzyme and the analogy of a hand fitting in a glove is seen as being a more accurate representation of what happens (induced-fit theory).

Many enzymes have an inactive form that becomes converted to an active form. The rate of conversion is determined by chemical conditions within the cells. The substrate enters the enzyme-combining site when the enzyme comes into contact with the substrate. The enzyme works: By rearranging existing molecules. or By breaking down the substrate molecule. or By combining several substrate molecules. E.g. catalase has 4 combining sites in each molecule for hydrogen peroxide. It speeds the break down of hydrogen peroxide by distorting the shape of the hydrogen peroxide molecule so that oxygen is given off and water left behind. The combining site can then take another molecule of hydrogen peroxide. Enzymes are classified according to the type of reaction they initiate, e.g.:

  • Anhydrases remove water.
  • Atpases split ATP.
  • Dehydrogenases remove hydrogen.
  • Kinases add phosphate.
  • Lipases break down lipids or fats.
  • Oxidases add oxygen.
  • Proteases break down proteins.

Sometimes a gene is defective, so that the instruction to produce a particular enzyme is inadequate. This results in a partially or completely non-functioning enzyme. When this occurs, the molecule normally converted by that enzyme (the substrate) builds up and the molecule produced by the enzyme is scarce. This can result in the accumulation of a substrate that may be toxic to us and/or a deficiency of a vital component for cellular health. These problems are referred to as metabolic diseases. Although they are present from birth, they may not manifest until later in life. Sickle cell anaemia, cystic fibrosis and lactose intolerance are examples of metabolic diseases.

We sell a digestive enzymes kit, plus there are other enzymes in the body biochemical kits. (These can be used by kinesiologists, EAV practitioners in their work. They are not suitable for lab use or by the general public.)

Copyright 2007 Jane Thurnell-Read

 

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