ENZYMES

PHYSICAL CHEMISTRY

Enzymes

Objectives:

Regulation of The metabolic processes that take place in living cells is of atmost importance. This regulatin occurs mainly by affecting enzyme activity.

In this chapter we will speak on tha chemical nature of enzymes, their mechanism of action, specificity , inhibition and regulation. Factors affecting enzyme activityas well as biomedical importance of plasma enzymes will be discussed

Lec. Title PDF Swf
1 Chemical nature, Mechanism of action, Nomenclature
2 Enzyme specificity, Factors affecting enzyme activity
3 Inhibition of enzyme activity
4 Regulation of enzyme activity
5 Regulation of enzyme activity (cont.), Isozymes
6 Plasma enzymes, Classification of enzymes
7 Coenzymes


Enzymes >> Chemical nature, Mechanism of action, Nomenclature >> Lecture 1


Enzymes

Enzymes are biological catalysts; they are organic thermo-labile catalysts.
They accelerate the rate of chemical reactions without being consumed in the reaction.

Chemical Nature of Enzymes

All enzymes are protein in nature except ribozymes, which are ribonucleic acid (RNA) in nature.

Protein enzymes are classified into:

Simple protein enzymes, which are formed of protein only.
Conjugated protein enzymes, which are formed of two parts:
A- Protein part called apoenzyme.
B- Non-protein part called cofactor.
The whole enzyme is called holoenzyme.

The cofactor may be:

A- Coenzyme, which is organic, thermo-labile and loosely bound to the enzyme. Theyare mainly vitamin B derivatives e.g. flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleotide (NAD).
B- Prosthetic group, which is inorganic thermo-stable and firmly bound to the enzyme. They are usually metal ions as calcium and zinc ions.

Mechanism of Enzyme Action

Each enzyme has catalytic (active) site. The substrate binds to the enzyme at its catalytic (active) site forming an intermediate enzyme substrate complex.
The enzyme substrate complex undergoes a transition state.
Then it decomposes to give the free enzyme and end products.
In conjugated protein enzymes, the coenzyme acts as an acceptor for one of the products helping the cleavage of the enzyme substrate complex.


Enzymes>> Enzyme specificity, Factors affecting enzyme activity >> Lecture 2


Enzymes>> Inhibition of Enzyme Activity >> Lecture 3


Enzymes >> Regulation of enzyme activity >> Lecture 4


Enzymes >> Regulation of enzyme activity (cont.), Isozymes >> Lecture 5


Enzymes >> Plasma enzymes, Classification of enzymes >> Lecture 6
Plasma Enzymes


Enzymes >> Coenzymes >> Lecture 7

for more information please
visit
http://osp.mans.edu.eg/medbiochem_mi/cources/biochemistry/

1st year medicine
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Enzyme inhibition

Enzymes



MANY MANY VIDEOS ON ENZYMES
https://www.youtube.com/watch?v=51cJM6eeeHM