identification of biological molecules
TRANSCRIPT
Identification of Biological Identification of Biological MoleculesMolecules
ALBIO9700/2006JK
Testing for the presence of Testing for the presence of sugars (Benedict’s test)sugars (Benedict’s test)
ALBIO9700/2006JK
Testing for the presence of Testing for the presence of sugars (Benedict’s test)sugars (Benedict’s test)
ALBIO9700/2006JK
Testing for the presence of Testing for the presence of sugarssugars
ALBIO9700/2006JK
Testing for the presence of Testing for the presence of starch (iodine solution)starch (iodine solution)
ALBIO9700/2006JK
Testing for the presence of Testing for the presence of lipids (emulsion test)lipids (emulsion test)
ALBIO9700/2006JK
Sudan IIISudan III
• Tissue that has been ground up is Tissue that has been ground up is transferred to a test tube containing transferred to a test tube containing water and boiledwater and boiled
• Oil droplets will escape the tissue Oil droplets will escape the tissue and rise to the surfaceand rise to the surface
• Add 2 cmAdd 2 cm33 Sudan III, shake and allow Sudan III, shake and allow the oil to settlethe oil to settle
• Oil will be stained redOil will be stained red
ALBIO9700/2006JK
Testing for presence of Testing for presence of proteinprotein
ALBIO9700/2006JK
Biuret testBiuret test
• Suitable for soluble proteinsSuitable for soluble proteins• Add equal amount of 1% potassium Add equal amount of 1% potassium
hydroxide (KOH) to solutionhydroxide (KOH) to solution• Add a few drops of 1% copper (II) sulphate Add a few drops of 1% copper (II) sulphate
(CuSO(CuSO44) solution down the side of test tube) solution down the side of test tube
• A blue ring at the surface of the solution A blue ring at the surface of the solution indicates proteinindicates protein
• On shaking, the blue ring disappears and On shaking, the blue ring disappears and the solution turns purplethe solution turns purple
ALBIO9700/2006JK
Millon’s testMillon’s test
ALBIO9700/2006JK
• For insoluble proteinsFor insoluble proteins• 6 drops of Millon’s reagent to a small 6 drops of Millon’s reagent to a small
amount (3 cmamount (3 cm33) of solution or ) of solution or suspension of protein and boil for 5 suspension of protein and boil for 5 minutesminutes
• After cooling, add a few drops of 1% After cooling, add a few drops of 1% sodium nitritesodium nitrite
• If protein is present, a brick-red If protein is present, a brick-red precipitate appears on the surfaceprecipitate appears on the surface