Enzyme Catalysis

 Enzyme Catalysis

source : columbia.edu

Enzyme catalysis

1 . Enzymes are complex nitrogenous org. Compds. which are produced by living plants & animals.

2. They are high molecular weight protein molecules.

3. They  form colloidal solution in water & are very effective catalyst.

4. Many reactions occur in the bodies of animal & plants to maintain the life process. These reactions are catalized by enzyme. Therefore enzymes are also known  as biochemical catalysts & this phenomenon is known as biochemical catalysis.

Ex.1. Starch is converted into maltose by diastase enzyme-

(C6H10O5)n +nH2O ——-> C12H22O11
Starch                                               Maltose

(2) Maltose is converted into glucose by maltase enzyme
C12H22O11 + H2O——–> 2(C6H12O6) Glucose
(3) Glucose & fructose are converted into ethyl alcohol by Zymase enzyme-

C6H12O6——–> 2C2H5OH + 2CO2

(4) Urea is converted into NH3 & CO2 by urease enzyme-

NH2CONH2 + H2O——-> 2NH3+CO2

(5) Lipase enzyme converts oils & fats into glycerol.
Oil or Fat——> glycerol

Characteristics of enzyme catalysis-

1- Most efficient Catalyst-

The enzyme catalysed reactions are very fast in comparison to the reactions catalysed  by inorganic substances because activation energy of the reactants in presence of enzyme is low.

2- Highly Specific Nature

Every  Enzyme is specific for a reaction i.e. one enzyme can not catalyse  more than one reaction.

3 -Effect of temperature

The action of an enzyme  depends upon the temperature . The temp. at which enzyme activity is maximum is known as optimum temp. The  optimum temp. of enzyme reaction occuring in the human body is 37 degree C. The favourable temperature range for enzymatic activity is  25-37 degree C . The activity of enzyme is destroyed at 70 degree C.

4- Effect of pH

The rate of an enzyme catalyse reactions varies with pH. The enzyme activity is maximum at particular pH called optimum pH.

5- Colloidal Nature

Enzymes formed colloidal solution in water. Enzymes are destroyed by UV-rays.

6- Activators or Co-enzymes

The enzymatic activity is increased in the presence of certain substances  Known as co-enzyme. When a small amount of vitamin is present along with enzyme then enzymatic activity is increased. Activators are generally metal ions i.e. Na+,CO++, Cu++  etc.

7 -Inhibitors or Poison

Enzymes are also poisoned  by the presence of certain substances . The poison interact with the active functional groups of the enzyme . It reduces & completely destroys the catalytic activity of enzyme. The use of many drugs & few inorganic substances  such as HCN, CS2, H2S acts as poisons for enzyme.

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