Biochemistry lab report Example | Topics and Well Written Essays - 2500 words

Biochemistry - Lab Report Example Paper chromatography is mainly used for separation of molecules and consists of cellulose with hydrophilic characteristics. The rate of movement of biomolecules depends on the affinity of the molecule and the solvent with hydrophobic molecules moving faster than the hydrophilic due to the little attraction of the molecule to the hydrophilic paper. Paper chromatography helps in the characterization of amino acids due to the different rates of movement of the amino acids on the chromatographic paper. Additionally, the different amino acids move at different rates on the chromatographic paper due to the differences in the size of the side chains. The rate at which a biomolecule moves on the chromatographic paper is expressed as its relative mobility (Rf). A mobile phase for use in the chromatography was prepared by mixing 60cm3 of ethanenitrile (acetonitrile) with 40cm3 of 0.1M ammonium ethanoate. Drops of concentrated ethanoic acid were used to adjust the pH value to 7.2 after which 30cm3 of this mixture was placed in a tall form beaker and cover it with a watch-glass. Small amounts of trypsin, leucine, valine, proline, glutamic acid, glycine and lysine amino acid solutions were prepared in water and each amino acid labelled. A faint line was drawn using a pencil on the lantern-type chromatography paper making sure that the line was above the level of the solvent in the beaker. Using a clean capillary tube each time, one small spot of each amino acid solution was put on the chromatography paper and each spot identifies and marked. An unknown sample was also spot on the paper and marked. The spots were dried using a warm air blower. The chromatographic paper was then bent around the cylinder and fixed in this shape using a paperclip. The chromatographic paper was then placed inside the beaker so that it stood on the edge without touching the sides and the chromatogram run until the solvent front moved three quarter way in the