what is electrophoresis polyacrylamide gel electrophoresis

1. ELECTROPHORESIS
Presented by :- Patel Vanita L .
CBO :- 406
M.Sc Sem :- 2
Department of life sciences ,
H.N.G.U., Patan

2. CONTENT
• What is electrophoresis ?
• Polyacrylamide gel electrophoresis
1. Native page
2. SDS Page

3. What is electrophoresis ?
• Electrophoresis is a technique used in laboratories in order
to separate macromolecules based on size . The technique
applies a negative charge so proteins move towards a
positive charge . This is used for both DNA and RNA analysis
.
• Electrophoresis is an analytical method frequently used in
molecular biology and medicine .
• It is applied for the separation and characterization of
proteins, nucleic acids, and sub cellular sized particles like
viruses and small organelles .

4.  It’s Principle is that charged particles of sample migrate in an applied
electric field.
 Type of electrophoresis :-
1. Polyacrylamide gel electrophoresis
2. 2- D Gel electrophoresis
3. Paper electrophoresis
4. Immuno electrophoresis

5. Polyacrylamide Gel electrophoresis :-
• Electrophoresis techniques separate charged molecules in an electric
field .
• The mobility of a molecule in inversely proportional to its size and
directly proportional to its charge .
• During Electrophoresis proteins move towards an oppositely charged
electrode in an electric field .
• Polyacrylamide gel electrophoresis is a technique based on this idea
and is used to separate proteins on the basis of their size .

6.  Two type of PAGE :
1. Native PAGE
2. SDS PAGE
1 . Native PAGE :-
Principle :-
In Native PAGE protein mixture are separated on The bases of
their molecular weight under the influence of applied voltage this are is
principle of Native PAGE .

7. Native( Buffers ) Gel :-
• In Native or buffer gels polyacrylamide gels are again used ( normally a
7.5% gel ) but the SDS is absent and the proteins are not denatured
prior to loading .
• Since all the proteins in the sample being analysed carry their native
charge at the pH of gel (normally oh 8.7 ) protein separate according
their different electrophoretic mobilities and the sieving effects of the
gel .
• It is therefore not possible to predict the behaviour of a given protein
in a buffer gels, but because of the range of different changes and size
of protein in a given protein mixture , good revolution in achieved .

8. • An alternative method for enzyme detection is to include the substrate in
an agarose gel that is poured over acrylamide gel and allowed to set .
• Diffusion and interaction of enzyme and substrate between the two gels
results in colour formation at the site of enzyme .
• Often , duplicate sample will be run on gel , the cut in half and one half
stained for activity the other for total proteins .
• In this way the total protein content of the sample can be analysed and
the particular band corresponding to the enzyme identified by reference
to the activity stain gel .

10. SDS (Sodium dodecyl sulphate ) PAGE :-
• SDS PAGE is the most widely used method for analysing protein
mixtures qualitatively .
• It is Particulary useful for monitoring protein purification and because
the method is based on the separation of protein according to size it
can also be used to determine the relative molecular mass of proteins
.SDS is anionic detergent .
• Each protein in the mixture is therefore fully denatured by this
treatment and opens up into rod-shaped structure with a series of
negatively charged SDS molecules along the polypeptide chain .
• The original native charge on the molecule is therefor completely
swamped by the negatively charged SDS molecules .

11. • Once the samples are all loaded a current is passed thorough the gel .
• The sample to be separated are not in fact loaded directly into the main
separating gel .
• When the main separating gel has been poured between the glass plate
and allowed to set shorter stacking gel is poured on top of the
separating gel and it is into this gel that the wells are formed and
proteins loaded .
• The purpose of this stacking gel is to concentrate the protein sample
into a sharp band before it enters the main separating gel .

12. • This is achieved by utilising differences in ionic strength and pH between
the electrophoresis buffer and involves a phenomenon known the
istachophoresis .
• The stacking gel has a very large pore size which allows the proteins to
move freely and concentrate or stack under the effect of the electric field
.
• Small proteins migrate faster through the gel under the influence of the
applied electric field .

14. Application for PAGE :-
• Separation of molecules .
• Prediction of molecule weight of separated molecule .
• You can study separate isoenzyme by use PAGE .
• This Technique is utilize of separation of the protein .

15. REFREENCES
• Principle and techniques of biochemistry and Molecular
biology :
by :- Keith Wilson
John Walker
 https://www.ncbi.nlm.nih.gov

16. THANK YOU