Linked Data in Production: Moving Beyond Ontologies
Practical 4 sec
1. HBC 1019 Biochemistry 1 Trimester 1, 2012/2013
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Practical 4: Protein Separation; Size Exclusion Chromatography (SEC)
Objectives
1. To learn basic gel filtration chromatography techniques.
2. Compare and contrast the use of different types of column chromatography in
the purification of protein.
3. Explain how naturally occurring or recombinant proteins are separated and
purified using column chromatography.
4. Discuss how the structure and biochemical properties of proteins relate to
purification using column chromatography.
5. Apply the scientific method to solve problems.
Introduction
Chromatography is commonly used in biotechnology for separation or purifying
biological molecules, like proteins. The principle of chromatography that involve with
mobile phase (solvent and the molecules to be separated) and stationary phase either
paper (in paper chromatography), or glass beads, called resin (in column
chromatography), through which the mobile phase travels. Molecules travel through
the stationary phase at different rates because of their chemistry. However, different
medium may have different way to perform the separation technique.
Some of the common types of chromatography are gel filtration chromatography,
affinity chromatography and ion exchange chromatography.
In gel filtration chromatography, commonly referred to as size exclusion
chromatography (SEC), microscopic beads which contain tiny holes are packed into a
column. When a mixture of molecules is dissolved in a liquid and then applied to a
chromatography column that contains porous beads, large molecules pass quickly
around the beads, whereas smaller molecules enter the tiny holes in the beads and
pass through the column more slowly. Depending on the molecules, proteins may be
separated, based on their size alone, and fractions containing the isolated proteins can
be collected.
2. HBC 1019 Biochemistry 1 Trimester 1, 2012/2013
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The mass of beads within the columns is often referred to as the column bed. The
beads act as “trap” or “sieves” and function to filter small molecules which become
temporarily trapped within the pores. Larger molecules pass around are “excluded”
form, the beads. Each column provided in this practical is prefilled with beads that
effectively separate or “fractionate” molecules that are below 60,000 daltons. As the
liquid flows through the column, molecules below 60,000 daltons enter the beads and
pass through the column more slowly. The smaller the molecule, the slower they
move through the column. Molecules greater than 60,000 pass around the beads and
are excluded from the column – also referred to as the exclusion limit.
This practical is made for the purpose to separate color molecules BSA (molecular
weight of 67,000 daltons, blue in colour) and vitamin B12 (molecular weight of 1,350
daltons, yellow in colour) to illustrate the principle of SEC. The process of separation
of these molecules can be visualized easily as they pass through the chromatography
column.
Materials, reagents and equipments
Protein Mix that contains BSA (Bovine Serum Albumin) and Vitamin B1
Size exclusion chromatography columns
Column buffer
12 Collection tubes
Test Tube rack for holding 12 tubes
Pipette (1ml)
Methods
12 collection tube were placed in the test tube rack. 10 of the collection were
labeled sequentailyfrom 1 – 10. The other two remaing were labled waste and
column buffer .
4 | of culmn buffer wre pipette into the tube labled column buffer
The seal of the both ends of the chromatography column were removed. The
entire buffer wasdraind into the waste collection tube.
3. HBC 1019 Biochemistry 1 Trimester 1, 2012/2013
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The column was placed gently onto the colletion tube 1. The column should not
jammed tightly into collection tube as the column will not flow. The protein
sample was ready to be loaded onto the column.
The end seal from the column was removed. The top of the column bed was
observed to make sure all of buffer had drained out from the column.one drop of
protein mix was loaded carefully onto the top of the columnbed. The pipette was
been inserted into the column and the drop are loaded just above the top of the
column so that minimally disturb the column bed.
The protein mix was allowed to enter the column bed. 300 ml of column buffer
were added carefully to the top of the column. The drops was started to be
collected into tube 1.
When all the liquid had drained out from the column, another 300 ml of column
buffer were added to the top of the column. The buffer was added as before by
placing pipette just above the top of the column. The protein mix had entered the
column far enough therefore the slight disturbances to the column bed would not
affect the separation. The column was transferred to test 2 and drop was counted.
5 drop of buffer were collected in the test tube 2.
When5drops had been collected into tube 2, the column was transferred onto tube
3. 5 drops of the buffer were collected into each of the collection tube. When 5
drop had been collected into a tube, the column was lifted to the next tube.
For the final tube 10 drops of the buffer was collected. All column were caped
when finished collecting the drops. The sample and column were stored according
to the tutors 'instruction'
4. HBC 1019 Biochemistry 1 Trimester 1, 2012/2013
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Results and observations
Tube 1 Pink Fast
Tube 2 Pink Fast
Tube 3 Yellow Slow
Tube 4 Yellow Slow
Tube 5 Yellow Slow
Tube 6 Yellow Slow
Tube 7 Yellow Slow
Tube 8 Yellow Slow
Tube 9 Yellow Slow
Tube 10 Yellow Slow
Discussion
The two differnet column chromatography techniquesare gel filtration
chromatography (SEC), affinity chromatography and ion chromatography.
Gel filtiration (SEC) is being used in this lab activity.
Microscopic beads wich contain tiny holes are packed into a column, when a mixture
of molecules is dissolved in a liquid and then applied a chromatography that contain
5. HBC 1019 Biochemistry 1 Trimester 1, 2012/2013
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porous beads. Large molecules pass quikly around the beads, whereas smaller
molecules enter the tiny pores in the beads and pass through the column more slowly.
Depending on the molecules, proteins might pass quicklyand sparated based on their
size alone fraction containing isolated protiens can be collected.
BSA would be excluded while vitamin B12 is fractionated. BSA will pass more
quickly through the column and appear in the early collectiontubesof fractio. Vitamis
are fractionated by the column. Vitamin will penetrate the pores of the beads
becoming temporarily trapped as a result they pass much slower and appear in the
later fraction.
More buffer are added after the protein mixture was laded onto column in order to
keep the BSA and vitamin mixture in a fluid phas. This ensure that the fluid phase ill
move through the column resulting in completion of the separation process.
BSA molecule exited the column first, and yes this is molecule is much larger of the
two
Based from the situation given, myosin will be the first molecules to appear as it is the
largest followed by hemoglobin as it is the intermediate and the third molecules to
appear is the myoglobin as it is the smallest.
Conclusion
BSA excited the column fisrt followed by vitamin B1.BSA is much larger than
vitamin B1 and so it would be expected to exit first from the size exclusion column.
Reference
www.main.uab.edu