Thursday, 19 November 2020

What is an Enzyme? Overview of this Amazing Biocatalyst.

Human body is a product of different chemical reactions and processes but what controls these reactions? in 1833 a french chemist, Anselme Payen was the first to discover the vital force that drove these reactions and named it "Enzyme" Enzymes are substances, proteins, or in some cases ribonucleic acid (rRNA) that speed up a biochemical reaction by modifying spesific substances called substrates.

Enzymes are supremely selective in who they binds to and modify, hence their specificity mode of action easier said but how does a tiny enzyme speed up a chemical reaction? the answer to this is simple enzymes perform this critical task by luring a reaction's activation energy that is the amount of energy needed for the reaction to begin enzymes binds to their substrates hold them, in such that chemical bond breaking and bond forming processes take place.

More easily enzymes have a spesific place in them called "active site" where the  substrate binds and real time action takes place.

Active site has a specific size, shape, and chemical behavior. Rendered to it by specific arrangements of amino acids. Thanks to these amino acids an enzyme's active site is unique only to a particular substrate in addition to the active site. Many enzymes consists of a non protein part called cofactor. Cofactors may be cations (positively charged metal ions).

Activators bound temporarily to the active site to activate the enzyme. Organic molecules vitamins or vitamin products coenzymes that joins enzyme substrate complex temporarily, prosthetic groups joins enzyme permanently. Enzyme bound many enzymes only perform their catalytic role when associated a coenzyme an inactivated enzyme, protein along with its coenzyme, non protein makes up a system called "Holoenzyme" to add to the complexity scientists terms this inactivated enzyme as "Apoenzyme" and therefore, the equation becomes Holoenzyme = Apoenzyme + Coenzyme.

Models of enzyme action lock and key hypothesis, this is the simplest model to represent how an enzyme works the substrate. simply fits into the active site to form a reaction intermediate. Just like the key fits in its specific lock the shape isn't changed. here rather the structure of the substrate absolutely compliments the structure of the enzyme like puzzle pieces.

Induced fit hypothesis in this model the enzyme, upon binding its substrate changes shape the matching between an enzyme's active site and the substrate isn't just like two puzzle pieces fitting together rather, the enzyme changes shape and binds to its substrate even more tightly. This fine tuning of the enzyme to fit the substrate is called "Induced Fit".

Types of Enzyme 

 A hydrolase,which catalyses the hydrolysis of a chemical bond, which effectively separates a molecule into two pieces,

 A lyase, which also cleaves covalent bonds, but by means other than hydrolysis.

 An enzyme with the opposite function, a ligase, is an enzyme that joins two molecules together. 

 A transferase is an enzyme that transfers a functional group from one molecule to another.

  An isomerase catalyses a spatial rearrangement of the substrate.

  An oxidoreductase is an enzyme that transfers electrons from one molecule to another.


  Environmental effects on enzyme function active sites are very sensitive they sense even the slightest change in the environment and respond accordingly some of the factors that affect the active site and consequently enzyme function include Temperature. The suitable temperature for enzymes to function properly is 37 degrees celcius. increasing or decreasing the temperature above 37 degrees celcius affects chemical bonds in the active site, making them less suited to bind substrates. Higher temperatures denature enzymes pH.

Amino acids present in the active site are acidic or basic fluctuation in pH, can affect these amino acids making it hard for substrates to bind extreme pH values can denature enzymes.

Enzyme concentration increasing
Enzyme concentration will increase the rate of reaction. As more enzymes will be available to bind with the substrates however after a certain concentration any increase will have no effect on the rate of reaction substrate concentration.

Increasing substrate concentration increases the rate of reaction this is because more substrate molecules will be colliding with enzyme molecules. so more product will be fought but again, this effect is valid up to a certain concentration.

Inhibition of enzyme activity some evil substances called "inhibitors" reduce or even stop the activity of enzymes in biochemical reactions they eat a block or distorts the active site. Thus inhibiting the reaction based on this there are two types of inhibitors given below
1) Competitive inhibitors occupy the active site and prevent a substrate molecule from binding to the enzyme.
2) Non competitive inhibitors attach to parts of the enzyme other than the active site to distort the shape of an enzyme.


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