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Proteins
(ACTIVITY 8)

Gallemit, Lacei Machelle• •
January 17, 2013

ABSTRACT
Chromatography is one of the most useful methods of separating minute amounts of complex mixtures into the pure substances contained therein. Chromatographic separations are effected by allowing the components in the mixture to be distributed in two phases, one being stationary, and the other, mobile. Partition chromatography involves two main distribution systems, one system is composed of a gas and a liquid and the other consists of two liquids. One type of partition is paper chromatography. The stationary phase of this system is a filter paper saturated with water, along which moves an immiscible solvent carrying the solute. The mobile solvent moving over the paper allows the separation of the solutes of different partition coefficients, hence the formation of a chromatogram. The ratio of these two rates of travel is called the Rf value and can be defined as the ratio of the distance traversed on the paper by the substance to the distance traversed by the mobile solvent from the same starting point. The objectives in this experiment is to learn how to use the paper chromatography technique, identifying and calculate the Rf of each amino acids and compare the Rf values and determine the unknown amino acid. DATA AND RESULTS

Table 1.
| Distance traveled by Amino Acid in cm| Distance traveled by solvent in cm| Rf Values| Glycine| 2.9| 5.3| 0.54|
Lysine| 3.1| 5.3| 0.58|
Aspartic| 1.2| 5.3| 0.22|
Glutamic| 2.3| 5.3| 0.43|
Unknown| 3.3| 5.3| 0.62|

Identity of unknown: Methionine

DISCUSSION

A series of procedures was followed to identify the different types of amino acids. A chromatography paper was obtained by wearing gloves and a line was drawn 6mm from the bottom paper. Five marks were made at 1 cm intervals along the line. Each amino acid sample was taken and lightly dotted on each pencil mark by using a micropipette. The solvent...
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