The application of enzymes in industry and medicine.

The application of enzymes in industry and medicine

Enzymes are proteins, made up of polypeptide chains of amino acids. They are biological catalysts to regulate the speed of many processes, and are used in industry and medicine, but in different ways. Enzymes are globular proteins, with their structure held together by hydrogen bonds and can therefore be denatured easily if these bonds are broken. This is because their structure is very important in the way they work. They have an active site, which is the area in which substrates are broken down into product molecules, and if this is altered the enzyme can no longer function. Immobilised enzymes are attached to inert insoluble materials so that the enzymes can be held in place during the reaction, removed and reused.

Enzymes are used in industry because they speed up reactions producing products which can be used as they are, or can be used to make different products. They can be used whilst within cells or micro-organisms, or they can be extracted and isolated. They are often immobilised once extracted, so that the enzymes can be reused.

One example of how enzymes are used in industry is in detergents. They have been used since the mid 1960’s and are used in biological washing powders, tablets and liquids, and are also used in dishwashing detergents. There are many different enzymes used in these detergents, because enzymes are specific therefore different ones are needed to target different stains. Proteases are used which act on protein-based stains from substances such as egg, grass, blood, meat and human sweat. Lipases in detergents act on stains from fat and oil based products. Cellulases are now included because they can reduce “bobbles” on clothes because they can remove cellulose fibres which cause this. Biological washing powders must be used at temperatures which are around 40oC because otherwise the enzymes involved would be denatured and no longer work. This also saves energy, and therefore expense.

Some of these enzymes are also used in dish washing detergents to produce effective stain removal. Using biological washing detergents is also better for the environment than non biological detergents because these often are more difficult to dispose of.

Enzymes are used in the fermentation of sugars to produce ethanol, which can be used in alcoholic drinks or as a fuel. It is used as a fuel mostly in countries where sugar is easily grown in vast quantities. An enzyme in yeast, Zymase, can break down simple sugars into ethanol and carbon dioxide:

C6H12O6 → ...

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C6H12O6 → 2C2H5OH + 2CO2

This process also makes other products, so that the combination made only contains around 10% ethanol. This is distilled in various different processes to give a solution of 95% ethanol concentration. More than half of industrially used alcohol, excluding beverage alcohol is produced in this way.

Some people and cats are lactose intolerant, and therefore cannot drink normal milk because of its lactose content. Lactose-free milk can be produced by using immobilised enzymes. The enzyme lactase is used, and is immobilised into “beads” by mixing the enzyme with sodium alginate solution, then dropping this into calcium chloride solution to form the beads. The beads are then placed in a column and normal milk is run through the column and collected through a tap. The lactose is converted into glucose and galactose. The milk has to pass through the column at a fairly fast speed because the product galactose is an inhibitor for the reaction.

Enzymes have many important uses in medical diagnoses and treatments. They are used widely to test for diabetes, and for diabetics themselves to test their blood sugar levels. The samples tested are either urine or blood samples. The enzyme glucose oxidase is used to catalyse the reaction:

Glucose + O2 + H2O → gluconic acid + H2O2

It is then possible to obtain a quantitative estimate of the amount of glucose present by using a second enzyme, peroxidase to convert a colourless hydrogen compound to a coloured compound:

DH2 + H2O2 → 2H2O2 + D

(D = coloured product)

The amount of D present can be measured with a colourimeter, and is used in hospitals to diagnose diabetes.

Diabetics can use Clinistix to monitor their blood/urine glucose levels to see how much insulin is needed. Clinistix are dipsticks which can detect the glucose levels in blood/urine. On the end of the stick is a cellulose pad containing the enzymes glucose oxidase and peroxidase, and when dipped in a sample the pad changes colour and the glucose level can be determined by comparing the colour to a colour chart. This is a simple method which gives almost instantaneous results, and is specific for glucose and will not show other sugars present in blood/urine and is therefore very reliable.

Enzymes are used therapeutically to treat some diseases. They are usually used to replace enzyme deficiencies in patients. In the treatment of acute lymphocytic leukaemia, asparaginase is used. Tumour cells are unable to produce the amino acid L-asparagine and therefore extract it from body fluids. Asparaginase does not affect normal cells functions but creates a state of starvation in the tumour cells because it stops the amount of extra L-asparagine being available to them. This treatment is around 60% successful in a study of 6000 patients who had the enzyme intravenously administered.

Blood clotting enzymes are used to treat haemophilia and cause the blood to clot, and proteases are used in blood thinning treatments to prevent dangerous blood clots.

It is thought that enzymes may be able to treat genetic diseases but at present it is not possible to easily target specific cells that need treatment, for example mucus cells in the lungs of cystic fibrosis sufferers could be targeted and made to stop producing excess mucus.

Without enzymes, many products would be impossible to manufacture, or the processes used to make them would be made much more costly and less simple to use. The use of enzymes in medicine is incredibly important in treating many diseases, which could otherwise be fatal.

Bibliography

Encarta 96 Encyclopedia

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