Enzymes are the catalysts or chemical substances synthesized in living cell and responsible for metabolic activities within the organism. Subatances which react with the help of enzymes are called "Substrates" and materials produced as the result of a chemical reaction are called "Products". Active sites are present on the surface of enzyme to combine with a substrate through hydrogen bonds or ionic forces. Substrates and enzyme combine to form enzyme-substrate complex. It involves a "lock and key" machanism in which some part of substrate establishes a close fit into some part of enzymes.
Enzymes are essentially proteins. But some of them consists of protein part called "apoenzyme" ans a non-protein part called "prosthetic group". Prosthetic group is divided into two catagories i-e activators and coenzymes/cofactors. Acticator is the inorganic metal portion attached to apoenzyme to help in binding a substrate to the enzyme. Loss of activator causes the inactivity of an enzyme. Some known acticators are copper, calcium, cobalt, iron etc. Coenzyme is the organic prosthetic group of enzyme. Coenzymes have loose association with enzyme acts as donors or acceptors of atoms in forming enzyme-substrate complex. Some coenzymes are NAD (nicotinamide adenine dinucleotide), NADP (nicotinamide adenine dinucleotide phosphate), FAD (flavin adenine dinucleotide) and COA(coenzyme A). Certain vitamins also act as coenzymes.
Some specific features of enzymes differentiate them from inorganic catalysts as enzymes are specific in their action associated with particular chemical reaction, these are not as passive during reaction as catalysts as sometimes molecules of enzymes get destroyed during reaction and velocity of a reaction is not always proportional to the concentration of the enzyme. But usually enzymes retain themselves during the reaction and can be reused for some other reaction. The chemical reactions involving enzymes are reversible if product get accumulated for a long time.
Enzymes catalyses a reaction by reducing the its energy of activation to make molecules more reactive. It brings the substrates closer either binding them in closer association or putting them under stress or strain. Activation energy is the energy required to start a chemical reaction. Enzymes can bring about those reactions at low temperature which only occur at high temperature. So it also act in the place of "thermal agitation".
Enzymes are essentially proteins. But some of them consists of protein part called "apoenzyme" ans a non-protein part called "prosthetic group". Prosthetic group is divided into two catagories i-e activators and coenzymes/cofactors. Acticator is the inorganic metal portion attached to apoenzyme to help in binding a substrate to the enzyme. Loss of activator causes the inactivity of an enzyme. Some known acticators are copper, calcium, cobalt, iron etc. Coenzyme is the organic prosthetic group of enzyme. Coenzymes have loose association with enzyme acts as donors or acceptors of atoms in forming enzyme-substrate complex. Some coenzymes are NAD (nicotinamide adenine dinucleotide), NADP (nicotinamide adenine dinucleotide phosphate), FAD (flavin adenine dinucleotide) and COA(coenzyme A). Certain vitamins also act as coenzymes.
Some specific features of enzymes differentiate them from inorganic catalysts as enzymes are specific in their action associated with particular chemical reaction, these are not as passive during reaction as catalysts as sometimes molecules of enzymes get destroyed during reaction and velocity of a reaction is not always proportional to the concentration of the enzyme. But usually enzymes retain themselves during the reaction and can be reused for some other reaction. The chemical reactions involving enzymes are reversible if product get accumulated for a long time.
Enzymes catalyses a reaction by reducing the its energy of activation to make molecules more reactive. It brings the substrates closer either binding them in closer association or putting them under stress or strain. Activation energy is the energy required to start a chemical reaction. Enzymes can bring about those reactions at low temperature which only occur at high temperature. So it also act in the place of "thermal agitation".
0 comments:
Post a Comment