Enzymes, the fuel of chemical reactions

Heyyy everyone! So sorry for my delay in posts! Haven’t been that well for a while so you know besides going to classes my bed was my best friend! 🙂 So let’s get started! In biochem 1362 we started off with Enzymes last week. Enzymes are globular proteins and they act as biological catalysts.Catalysts speed up the rate of chemical reactions just as how fuel may speed up the rate of a car. Enzymes are coiled into a precise 3D shape with hydrophilic side chains on the outside of the molecule. Enzymes have an active site which the  substrate molecules bind. The active site is made up of only a few amino acids. These catalytic amino acids are often some distance apart in the protein chain but are brought into close proximity because of the folding of the chain.

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Photo credit- http://www.catalysis-ed.org.uk/principles/images/enzyme_substrate.gif

NB- Each type of enzyme acts on one type of substrate molecule because of the precise shape. ie the enzyme is specific. Enzymes may catalyze a reaction in which a substrate molecule is split into 2 or more products or it may catalyze the joining together of 2 molecules.(eg to make a peptide bond)

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Photo credit – http://www.chem.ufl.edu/~itl/2041_f97/matter/FG14_013.GIF

In order for the rock to reach from point A to Point B energy must be activated. Before reactions take place, they must overcome an energy barrier by exceeding the activation energy which simply means that a small amount of  extra energy must be supplied. Activation energy is therefore the minimum energy needed to carry out a particular chemical reaction. Enzymes lower the activation energy and allow reactions to take place more readily. The usual source of energy is heat but enzymes allows reactions to take place at lower temperatures.

General Properties of Enzymes

> They are globular proteins

> Affected by temperature/pH and substrate concentration

> They are specific

> They are unchanged at the end of chemical reaction

> They catalyze reversible reactions

> The amount of enzyme alters the rate of the chemical reaction

Other sources:

1) http://www.bio-medicine.org/biology-definition/Activation_energy/

2) http://eplantscience.com/index_files/biotechnology/Microbial%20biotechnology/

     Enzyme%20Technology/biotech_enzyme_properties.php

3) http://www.abpischools.org.uk/page/modules/enzymes/enzymes4.cfm?coSiteNavigation_allTopic=1

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