Enzymes play a role in making different types of food. Cheese is made from milk with the help of rennin enzyme. Rennin helps coagulate milk curds and later cheese is made from curds. An enzyme called bromelain or pepin is mixed with the meat before cooking to soften the meat. Candy is made using invertase enzyme and softened with lactase enzyme. Enzymes are used to make ice cream and bread.

1. The role of enzymes in food preparation
Enzymes play a role in making different types of food. Cheese is made from milk with the help of rennin enzyme. Rennin helps coagulate milk curds and later cheese is made from curds. An enzyme called bromelain or pepin is mixed with the meat before cooking to soften the meat. Candy is made using invertase enzyme and softened with lactase enzyme. Enzymes are used to make ice cream and bread.
2. Role of enzymes in biological activities
(i) Pectic enzyme is used in making juice of mango, apple, grape etc.
(ii) It is used to remove large stains from clothes.
(iii) Enzymes are used to separate the hair from the hide in the tannery.

3. Use of enzymes in medicine
(i) Fermin or bromaline enzyme is used as anthelmintic.
(ii) Thrombin stops bleeding in the body. An enzyme called urobilase is used to dissolve blood clots in the brain and arteries.
(iii) The amount of uric acid and urea in the blood is determined by uricase and urease enzymes.
(iv) Enzymes called glucose oxidase and peroxidase are used to determine the blood sugar level of a diabetic patient.
(v) Enzymes like amylase, pepsin, lipase etc. are taken as medicines for stomach pain.
(vi) Trypsin is used in cataract surgery.
(vii) Using proteolytic enzymes can control hypertension and greatly reduce the risk of death.
(viii) Trypsin enzyme is used to clean body wounds.

4. Role of enzymes in biotechnology
(i) Recombinant DNA is produced using different types of enzymes in gene engineering.
(ii) Determining the base order of DNA and RNA and addition or subtraction of nucleotides.
(iii) DNA cleavage using restriction enzymes and joining of DNA fragments using lipase enzyme.
(iv) Necessary drugs are prepared from milk, blood and urine of animals using enzymes.

5. Role of enzymes in antibiotic production
In 1929, Alexander Fleming first produced the antibiotic Penicillin from Penicillium notatum, which saved the lives of many patients. It works against bacterial activity. It revolutionized medicine.
6. Role of Enzymes in Environmental Conservation
Today environmental protection has become a global movement. Enzyme technology has made it possible to save the environment. Biosensors are made using enzymes. These biosensors determine the amount of various pollutants present in the environment.
7. Enzyme for making fruit juice
Fruit juice is a popular food these days. Enzymes are used to make juice from fruits like mango, grape, apple, orange, pineapple etc. Cellulase and pectinase enzymes are used to clarify fruit juices.
8. Role of enzymes in digestion
Enzymes like pepsin, trypsin, chymotrypsin, aminotrypsin, peptidase etc. digest protein food to produce amino acids. Enzymes like tyalin, amylase, maltase, isomaltase, lactase etc. digest carbohydrates and convert them into glucose. Enzymes like lipase, phospholipase, lecithinase, cholesterol esterase, monoglyceridase etc. digest lipids to produce fatty acids and glycerol.
9. Uses of enzymes in industry
(i) Food processing: Amylase is used to make corn syrup from starch. Protease enzymes are used to reduce the protein content of biscuit dough. Cellulase is needed to process coffee. Catalase enzyme is used in the bakery industry to make sugar from starch.
(ii) Baby food: Trypsin is used to make baby food easier to digest.
(iii) In paper industry: Amylase is used in paper sizing and coating. Xylanase is used to reduce the amount of bleaching when decolorizing paper. Cellulase is needed to smooth the paper and reduce the water content of the paper. Ligninase enzyme is used to remove lignin from paper.
(iv) In Alcohol Industry: Amylase, Gluconase and Protease are used in the preparation of raw materials for alcohol. α amylase and β amylase are used in beer and wine making. Protease enzymes are used to remove turbidity in beer.
(v) In dairy industry: Rennin is used to make cheese from milk protein. In France, lipase is used to ripen sheep’s milk blue cheese. Lactase enzyme is required to make glucose and galactose from lactose.
(vi) In photography industry: Protease is used to clear gelatin from film.
(vii) In rubber industry: Catalase enzyme is required during manufacture of rubber from latex.
(viii) Biological detergents: Protease is used to remove protein stains from fabrics. Amylase is used to remove starch stains from clothes and dishes. Cellulase is used as a biological conditioner for fabrics. Lipase enzyme is used to remove oil and grease stains from fabrics.
(ix) In biofuel industry: Cellulase is used to produce ethanol in fermentation process.
(x) Ice cream making: Soft and malleable ice cream is made using lactase enzyme.
(xi) Candy making: Candy is made using invertase enzyme.
The use of enzymes in various research works including molecular biology is increasing day by day. Metabolism and life cannot exist without enzymes. So it can be said that the systemic activity of enzymes is life.

Enzymes that break down hydrogen peroxide to produce water and oxygen are called catalase. All organisms containing oxygen contain the enzyme catalase. Its production capacity is higher than all enzymes. One molecule of catalase produces hundreds of millions of water and oxygen from H2O2 per second. Uses or importance of catalog are-
(i) Catalase is widely used in dairy industry. Catalase enzyme is used to remove H2O2 from milk before making cheese.
(ii) It is used in textile industry. Catalase enzyme is used to remove H2O2 from fabrics.
(iii) It is used as eye contact lens cleaner.
(iv) It is used in food packaging to prevent oxidation of food.
(v) It is used to remove H2O2 from fabrics.

Enzymes that break down sugar or sucrose in the process of fermentation to produce ethyl alcohol and CO2 are called zymase. 25-370C. This reaction is carried out at temp. In 1897, Edward Buchner isolated the zymase enzyme from yeast. The use or importance of Zymage is-
(i) It is used commercially in the production of alcohol.
(ii) It helps in digestion of food.
(iii) It is used as a medicine for indigestion in the patient.

The enzyme that breaks down cellulose into cellubiose is called cellulase. The process of breaking down cellulose is called cellulolysis. Cellulase enzyme activity causes the carcasses to decompose into the soil. Cellulase enzymes are secreted from the digestive system of herbivores. Cellulase enzyme is not secreted in the human digestive system. Uses or importance of cellulase are-
(i) It is used as an ingredient in laundry detergents and washing powders.
(ii) It is used in making paper.
(iii) It has uses in the preparation of medicines.
(iv) It is an important component of textile industry.
(v) It is used in coffee processing.
(vi) It is used in the production of beverages and juices.

The enzyme that breaks down fats or lipids into fatty acids and glycerol is called lipase. The process of breaking down fat or lipids is called lipolysis. Uses or importance of lipase are-
(i) Lipase enzyme is used in the diagnosis of pancreatic disease.
(ii) It is used in making curd and cheese.
(iii) It has uses in bakery and detergent industries.
(iv) It is used in curd and cheese industry.
(v) It is used in digestion and transport of food.

The enzyme that breaks down amylose into maltose is called amylase. It is of two types. α-amylase and β-amylase. Plant seeds, bacteria and fungi contain both enzymes. Human saliva and pancreatic juice contain α-amylase. The pancreatic enzyme is α-amylase. β-Amylase plays an important role during seed germination. Uses or importance of amylase are-
(i) Amylase enzyme is used in replacement therapy (PERT) treatment.
(ii) It is used in the manufacture of liquor and beer.
(iii) It converts starch into sugar.
(iv) It is used in detergents.
(v) Amylase is used in bakery industry.
(vi) Amylase is used to clean clothes and dishes.

Enzymes that break down proteins into amino acids are called proteases. The process of breaking down proteins is called proteolysis. It is also called proteolytic or systemic enzyme. Protease enzymes digest protein-rich foods. For example, pepsin, trypsin, erepsin, papain etc. Uses or importance of protease are-
(i) Protease enzymes are used to improve bread quality.
(ii) It is used to control blood clotting.
(iii) It has uses in the preparation of medicines.
(iv) It breaks down animal carcasses and releases nitrogen and carbon into the environment.
(v) Protease enzymes are used in biological research.

1. Temperature: Enzyme activity increases with increasing temperature, but is destroyed at higher temperatures. The best temperature for enzymes is 35-400C. 00C. Most enzymes are inactivated by heat. The temperature is 450C. Above this, the enzyme denatures or denatures.
2. Water: Enzymes are inactive in the absence of water. Increasing the amount of water increases the rate of enzyme action.
3. pH : Enzyme activity is controlled by pH. The optimum pH of enzymes is trypsin-8.0, urease-7.0, cellubiase-5.0, invertase-4.5, pepsin-2.0 etc.
4. Substrate concentration: Enzyme activity increases as substrate concentration increases and enzyme activity decreases as substrate concentration decreases.
5. Enzyme concentration: Increase in enzyme concentration increases the rate of reaction and decrease in enzyme concentration decreases the reaction.
6. Co-enzymes: Enzyme activity increases in the presence of any co-enzyme. Eg ATP, ADP, NAD, NADP, FAD, FADP etc.
7. Metals or metals: The presence of metals both increases and decreases enzyme activity. Enzyme activity increases in presence of Mg2+, Mn2+ etc.
8. Oxidation: Some enzymes are activated by oxidation and are inactivated by exposure to mild oxidizing agents. For example, sulfhydryl.
9. Inhibitors: The presence of substances that temporarily or permanently stop the action of enzymes are called inhibitors. High energy radiation, salts of heavy metals, cyanide, dinitrophenol, formalin etc. are inhibitors.
10. Activator: Activator activates the inactive enzyme. Inactive pepsinogen is converted to active pepsin under the influence of HCl. Like Cl+, Mg++, Ca++, Mn++ etc.
11. Contact: Enzyme and substrate come into contact with each other and form compounds. Enzyme action occurs when the compound is formed.
12. Irradiation: High energy radiation (α, β and γ rays) causes structural deviation of the enzyme and reduces the activity.
13. Inhibiting agents: Metals whose presence inhibits enzyme activity are called inhibitory agents. Like Ag, Zn, Hg, Cu etc.

In 1966 D. Koshland presented the hypothesis of enzyme mechanism of action. The obsession doctrine can also be called a modified version of the lock-and-key doctrine. In this theory, the structure of the enzyme is variable. Such enzymes are called allosteric. The obsessional doctrine is discussed as follows:
A special type of protein is an enzyme. The site of apoenzyme where the substrate binds and causes the reaction is called the active site or reaction center. Enzymes contain one or more active sites. The size of the substrate and the size of the enzyme’s active site can vary. According to induction theory, the substrate does not require a specific conformation or affinity to bind to the enzyme’s active site. Rather, the binding of the substrate molecule requires some modification of the active site of the enzyme. Such modification makes the active site fit for the substrate. As a result, the substrate binds to the active site of the enzyme. The enzyme assumes its maximal catalytic shape after binding to the substrate. The substrate and enzyme are then joined by hydrogen bonding to form an enzyme-substrate complex. Once the enzyme-substrate complex is formed, the enzyme readily cleaves the substrate. At the end of the reaction, the product is freed from the bond and moved away and the enzyme is released unchanged. The free enzyme takes part in the new reaction.
The obsession theory has gained acceptance among many scientists. In support of this model, X-ray observations of carboxypeptidase-A and several other enzymes are presented
[According to D.Koshland, the active site of an enzyme consists of two parts. buttracing groups and catalytic groups. The buttracing group holds the substrate and the catalytic group helps to weaken various substances in the substrate to reactants]