WEEK 5 ENZYMES PT1!!!!!!!!!!!

funny enzyme picture

This week we did an introductory phase into the enzymic world where all the basics were covered so here goes…..

The definition of an enzyme   –

An enzyme is a biological catalyst that speeds up chemical reactions by providing an alternative pathway with a lower activation energy…  *note that a catalyst is something that changes things without being changed itself…

Things to know generally about an enzyme-

-Most are proteins except for a few like ribozymes (RNA molecules with catalytic properties) and abzymes  (antibodies with catalytic properties)..
– An enzyme does not change the free energy of the of the reactants or products . It does not change the equilibrium of the reaction but accelerates it.
-the no. of substrate converted to product per enzyme per second is called the turnover no. or K*cat

More on Ribozymes: http://chemistry.gsu.edu/faculty/Huang/ribozyme.htm

Criteria for RNA molecules to be considered enzymes:
1)they have specific sunstrates on which they can act on
2)speeds up reaction rate
3)remain unchanged after the reaction

Enzyme Nomenclature-

In the past it was very difficult to remember the names of all enzymes according to what reaction they catalyzed. Some are easy to figure out for e.g lipases, maltase sucrose etc., some like pyruvate carboxylase were a bit difficult to figure out but it was those like tripsin, catalase and rennin which gave no hint of their action/s that were a problem… Soo the IUBMB developed a way of breaking down the enzymes to a more easily notifiable way. This included categorizing them into six major classes,  with their respective subclasses and sub-sub classes. They all have a specific number assigned to whatever class, subclass or sub-sub class they belong to thus making them easily identifiable. Each enzyme now has 4 numbers with which to identify from and is called the E.C or enzyme commission number.
The following link provides ample information on how to name the enzymes using the numbers:    http://www.bio.davidson.edu/courses/genomics/2008/simpson/tutorial2.html

They are known for 3 main features:
-catalytic power


-they can accelerate a rx’n to 10^3 to 10^8 times faster than the uncatalysed reaction
-can catalyse 100-1000 substrate molecules to product per second

These youtube videos are very helpful in understanding enzymes:

…..there are many parts to this so you can just browse through the divided parts….

The following image shows differences and similarities between organic enzymes  and inorganic catalysts

differences and similarities between enzymes and inorganic catalysts