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Describe the important properties of enzymes.

Vidyadip · Accepted Answer

Following are the important properties of enzymes:
(1) Biological origin: All types of enzymes found in living organisms are synthesised in the cell and the reactions controlled by enzymes can take place inside the cell or outside the cell. All chemical reactions taking place in cells are controlled by enzymes and the reactions taking place outside the cell, such as the hydrolysis process by Rhizopus, a fungus growing on bread, take place outside the cell.
(2) Colloidal nature: Generally, due to the large size of enzyme molecules, they are colloidal in nature. All the properties of proteins like high molecular weight, colloidal behaviour, slow diffusion, movement towards electric current and inability to cross living membranes etc. are found in enzymes. Due to colloidal form, enzymes molecules have a very large surface area, on which there are many active sites. The presence of active site reflects the quantitative efficiency of enzymes.
(3) Molecular weight: The molecular weight of enzymes is high, like the molecular weight of Catalase and Urease is up to 2,50,000 and 4,83,000.
(4) Enzyme specificity: Every enzyme has specificity, it is of two types-
(i) Absolute specificity: When an enzyme is the catalyst for a particular substrate only. For example-Maltase enzyme only catalyses maltose into glucose.
(ii) Group specificity: When an enzyme is active on a group of base substances which are structurally related to each other.
(5) Catalytic properties: Catalysts are those chemical substances which accelerate chemical reactions without changing or destroying themselves. Despite being in small quantities, they accelerate the chemical reaction and reappear after the reaction ends. Hence the enzyme has all the properties of a catalyst. For this reason enzymes are called biochemical catalysts.
(6) Reversible properties: All enzyme catalysed reactions are reversible, that is, they accelerate the chemical reaction in both directions, like:
Fatty acid + Glycerol $\stackrel{\text { Lipose }}{\rightleftharpoons}$ Fat
(7) Quantitative efficiency: A very small amount of enzymes converts a large amount of substrate.
(8) Sensitivity: Enzymes are heat sensitive or thermolabile, that is, they get denatured or destroyed at high heat or temperature 55°C to 65°C. The maximum activity of the enzyme is between 25°C to 30°C, but the enzymes of dried seeds remain active even at higher temperatures of 100°C to 120°C (because the amount of water in them is very less).
(9) pH: Every enzyme has a certain pH for its activity. Most enzymes are most active between pH 6.0 and 7.5.
(10) Precursors of enzymes: In living cells, the precursors of enzymes remain in inactive state. These are called zymogens or proenzymes. Zymogen can be converted into enzymes with the help of some compounds. These compounds are called Kinases.
(11) Accelerate the rate of reaction: Enzymes accelerate the speed of chemical reaction. Enzymes do not affect the equilibrium of the reaction.

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