what are enzymes

WHAT ARE ENZYMES ?[ EVERY DAY SCIENCE] CSS/PMS/FPSC/PPSC

Enzymes can be defined as the reaction catalysts of biological system produced by living cells and are capable of catalyzing chemical reactions. Two remarkable properties of enzymes are their extraordinary specificity ( each enzymes catalyzes only one reaction or one group of closely related reactions) and their amazing efficiency.(https://eastwestknowledge.com/cyber-crime/)

These are either pure proteins or contain proteins as essential components and in addition require non-protein components which are also essential for their activity. the protein component of the enzyme is called apoenzyme and the non-protein component is called the co-factor or co-enzyme. Many enzymes contain vitamins as their co-factors and thiamine pyrophosphate contain Vitamin B1.

While naming of the enzymes, suffix-“ase” is added to the name of the substrate on which the enzyme acts, for example, urease, sucrase, cellulase are the enzymes, which act upon the substrate urea, sucrose and cellulose respectively.

https://s.click.aliexpress.com/e/_AXAUlK

CLASSIFICATION OF ENZYMES

The commission on enzyme, appointed by the International Union of Bio-Chemistry [IUB] classified enzymes into six main types.

[1] OXIDOREDUCTASES

These catalyze oxidation-reduction reactions. Common examples are oxides, dehydrogenase and peroxydase.

[2] TRANSFERASES

These bring about an exchange of functional group such as phosphate or acyl between two compounds, For example; phospho-transferases, etc.

[3] HYDROLASES

These catalyze hydrolysis. They include proteases called protolytic enzymes.

[4] LYASES

These catalyze the addition of ammonia, water or carbon dioxide to double bonds or removal of these to form double bonds, for instance phospho-glyceromutases.

[5] ISOMERASES

These catalyze the transfer of groups within molecules to yield isomeric forms of the substrate. For example is the conversion of fumaric acid to maleic acid in the presence of fumarase enzyme.

[6] LIGASES

These link two molecules together through the breaking of high energy bonds, for example, a carboxylase and succinic thiokinase.

PROPERTIES OF ENZYMES

There are following properties:

[1] SPECIFICITY

These are specific in their action which means that an enzyme will act on only one substrate or a group of closely related substrates. For example, hexokinase catalyses the conversion of hexoses like glucose, fructose and mannose to their 6-phosphate derivates but glucokinase is specific for glucose only.

[2] PROTEIN NATURE

Enzymes with few exceptions are protein in nature. They are produced by living cells but act in vivo as well as in vilro.

ENZYME REACTIONS

Most enzymatic reactions are reversible i.e. the same enzyme can catalyze reactions in both directions.

ISOENZYMES

These are the enzymes from the same organism which catalyze the same reaction but are chemically and physically distinct from each other.

FACTORS AFFECTING ENZYMES ACTIVITY

There are following factors affecting :

  • Enzyme Concentration.
  • Temperature.
  • Effect of pH ( power of hydrogen).
  • Radiation.

COMMERCIAL USES OF ENZYMES

These are used on commercial scale for different purposes. common types of enzymes and their role in industry is described as :

  • These are present in the yeast are commercially used for the fermentation of molasses and starch to produce alcohol (Ethanol). These enzymes are diastase, invertase and zymase.
  • Microbial enzymes are used in detergents (powder or liquid). Lipases decompose fats into more water soluble compounds. amylase removes starch based stains. Cellulase degrades cellulose to glucose, a water soluble compound. Bacterial proteases break down protein stains on the clothes. thus, enzymes containing detergents clean effectively and remove all stains and dirt.
  • These are used for the purification of fruit juices. they are added to fruit that has been crushed like grapes. The increases the yield of the juice extracted by removing suspended particles. It also improves the colour derived from the fruit skins.
  • Amylase enzymes are used in bread making because they can yield more starch of the flour. Even they are efficient enough to convert starch to sweet glucose syrup. This can be used as sweetner in the food as well as bread making.
  • Lactase enzyme is used to increase sweetness in ice cream. As lactose in milk is broken own to galactose and glucose, which are sweetner than lactose.
  • In the dairy industry some enzymes are used for the production of cheeses, yogurt and other dairy products while others are used to improve texture or flavours of the products.

CHARACTERISITCS OF ENZYMES

The biochemical catalysts process the following important characteristics.

  • All enzymes are globular proteins.
  • They increase the rate of reaction without themselves being used up.
  • Their presence does not affect the nature or properties of end products.
  • Small amounts of an it can accelerate chemical reactions.
  • They are very specific in their action; a single enzyme catalyzes only a single chemical reaction or a group of related reactions.
  • They are sensitive to even a minor change in pH, temperature and substrate concentration.
  • Some of it require a co-factor for their proper functioning concentration.
  • They lower the activation energy of the reactions.

PEPSIN ENZYME EXAMPLE

Some enzymes are potentially damaging if they are manufactured in their active form. for example, pepsin is a powerful protein. Digesting enzyme and is quite capable of destroying cell’s internal structure and thus is produced inactive pepsinogen form by the cell. It is converted in its active form only in the digestive tract where it is required to be active.

Total
1
Shares
Related Posts
Read More

INTRODUCTION OF HSK PART 2

CHINESE PROFIENCY TEST (HSK) HSK is the abbreviation of Hanyu Shuiping Kaoshi and is an international standard skill test for persons who are…