The other enzymes used are starch-splitting enzymes to reduce cloudiness (especially with apples), cellulase to improve juice yield and colour and arabanase to reduce the haze caused by the polysaccharide araban passing from the cell wall to the juice. 3
Textiles and the leather industries have been using the enzymes for more than simply desizing for over the past two decades.
The main enzymes used in the leather industry are proteases, which help in the dehairing of the animal hides and the removal of the excess tissue to make it more pliable, and lipases are used for degreasing. 10
In the textiles industry, enzymes are increasingly being used in the finishing of the fabrics. Also, enzymes are used to carryout the stonewashing process in the industry as they reduce the power usage and the waste emissions. 5 A main problem in the industry is the removal of the hydrogen peroxide. Traditional method is to neutralise the bleach but dose control is unfavourable. The enzyme catalase is used to breakdown the hydrogen peroxide into oxygen and water producing a cleaner waste, which is environmentally friendly. 5
In the food industry, protease is used to get rid of gluten in strong flour and lowers the protein content for biscuit production. Protease is also significantly important in medicine as it is used to extract heparin, which is used to prevent blood clotting during surgery. 1
Protease is also used to produce infant milk formulae from cows’ milk. The proteins found in the cows’ milk are different to the ones found in human milk. The bottle-fed babies may develop an allergy in response to the cows’ milk. Protease is used to digest the milk proteins into peptides and free amino acids therefore reducing sensitivity to cows’ milk. Degrading the proteins into peptides can improve the nutritional value of the treated milk. 5
As well as industry, enzymes play a very important role in medicine.
L-asparaginase is used to breakdown the L-asparagine. L-asparaginase is used for cancer therapy, as L-asparagine is an important factor in tumour growth. 2
Enzymes are also used to detect levels of different substances in the blood. Cholesterol oxidase is used to detect the cholesterol level in the blood by oxidising the cholesterol. 2 It is important to know ones cholesterol level because too much cholesterol in the blood can lead to blood vessels being blocked up with fat which may lead to heart related diseases. 10
Similarly, glucose is always measured by using the enzyme glucose oxidase.2 Strips of paper impregnated with glucose oxidase are used by diabetics to monitor their blood sugar. 10 Glucose oxidase metabolises the glucose when a drop of blood is added to the strip and a series of reactions produce a measurable colour change which is proportional to the amount of glucose. 10+8
Urokinase is an enzyme, which is used for the removal of fibrin clots after the heart attack by the plasminogen activation. 2 Another enzyme acetylcholinesterase is used for hydrolysis of acetylcholine and is needed for the operation of nerves. 9
Restriction enzymes occur naturally in bacteria and are used for the isolation of genes. They cut the DNA at a precise sequence of nitrogen bases. 1 They are widely being used in genetic engineering to produce the pieces of DNA which can be used in the cloning techniques. 5 These isolated genes are inserted into a vector or a carrier, which is usually a virus. Another enzyme, DNA ligase joins the isolated gene to the DNA of the virus. 1 This virus is transferred to the new host, which it attacks and injects its DNA containing the isolated gene. 1 This host cell would divide repeatedly and this way, organisms can be genetically engineered. 1
The increasing use of enzymes in everyday life clearly shows us their significance. Without them, we would be several years behind in technology compared to where we are today. At present, the international production of enzymes is worth £530 million per year. 5 The environmental advantages of enzyme technology are really very obvious. Their ability to work in mild conditions and at low temperatures has lead to a reduction in precise and harsh conditions. This in turn, saves energy and reduces the pollutants. Enzymes are obtained from natural resources and are eco-friendly, and their breakdown products – amino acids – are non-toxic. 6
Bibliography
Books
1) Givens, P. Reiss, M. ( ) Human biology and health studies
Some good detail about how enzyme works. Has a useful section on the uses of enzymes.
2) Freeland, P. (1999) Microbes, medicine and commerce
Hong Kong: Hodder and Stoughton educational
Some commercial uses of enzymes in a concise form. Some good detail about the functions of enzymes. Too much detail about immobilisation and biosensors.
3) Baker, M Indge, B. Rowland, M. (2000) AS AQA Biology specification A
A new introduction to biology
Italy: Hodder and Stoughton educational
Goes into good detail about everything related to enzymes that an AS level student may need to know, such as inhibition, activation energy, lock and key mechanism. Also has some information about the effects of temperature and pH on the enzyme activity.
4) Toole, G. Toole, S. (1987) New understanding Biology for advanced level (4th edition)
Cheltenham: Stanley Thornes
Some good detail on some uses of enzymes in industry. Goes into too much detail about enzyme structure and function, properties on enzymes, enzyme cofactors and classification of enzymes which is too much for this activity.
Journals
5) Denny, G. (May 2000) Enzyme technology. Biological sciences reviews
26 – 27
Some information about the history of the enzymes. Some useful detail about the uses of enzymes in selected industries. Language used is very scientific and is not very straightforward to follow.
6)Robson, G. Weibe, M. (Jan 2001) Enzymes from fungi. Biological sciences reviews 19 - 21
some detail about the fungal enzymes and fungi as cell factories which is not quite relevant for the topic. However, has a useful section on the uses of enzymes in the detergent industry.
Internet
7) http://www.educ.um.edu.mt/Educ/Dmste/StudentsProjects/
CoolScientists/enzymes/euse11.htm
A very easy and a straightforward website to follow. Provides information in bullet points and uses animations and graphics to present the information in a very simple form. Has a lot of information about what enzymes are and their properties but has a little about their uses.
8) http://www.dyadic-group.com/enzymes.htm
Has a lot of information about the enzymes. What they are, how they are produced, where their products are used. Uses a very scientific language and the examples given are very brief.
9) http://ull.chemistry.uakron.edu/genobc/Chapter_20/
Some good and brief examples about how enzymes are used in industry. A lot of basic in formation about the enzymes and their structure. A very simple website to follow.
10) http://www.enzymes.co.uk
Has a lot of information about the uses of enzymes in industries. Also has a little information on the uses of enzymes in pharmaceuticals.