EXP#6

• Nucleic Acid Hydrolysis


  A process of breaking nucleic acids (DNA or RNA) into constituent nucleotides through the addition of water
• Nucleic Acid Hydrolysis


  Cleavage (division) of phosphodiester bonds, which link nucleotides together in the nucleic acid polymer
• Sulfuric acid


  Acts as a catalyst to break down the DNA molecule into its individual components
• Chemical Reaction for DNA Hydrolysis using Sulfuric Acid


  H2O + DNA + H2SO4 → DNA hydrolysis products + H2SO4
• Dische Test


  • To detect deoxyribose of DNA
  • Positive result: The amount of blue corresponds to the amount of DNA in solution
• Fehling's Test


  • To detect the presence of carbohydrates in a solution; to differentiate between reducing and non-reducing sugars
  • Positive result: Reddish/brown precipitate
• Test for Purine Bases


  • To determine the presence of purine bases in a solution
  • Positive result: Gelatinous white precipitate
• Bial's Test


  • To detect the presence of pentoses and pentosans; for quantification of RNA in a sample
  • Positive result: Blue-green complex
• Test for Phosphate


  • To determine the presence of phosphate ions
  • Positive result: Yellow precipitate
• Acid Hydrolysis of DNA

  Breaking phosphodiester bonds between nucleotides using an acidic solution, resulting in cleavage of the DNA backbone and releasing individual nucleotides
• Products of DNA Acid Hydrolysis

  • Nucleotide bases: Adenine (A), Guanine (G), Cytosine (C), Thymine (T)
  • Deoxyribose sugar molecules
  • Phosphate groups
• Dische Test


  Principle & Chemical reaction: When heated, the reagent turns blue in the presence of DNA, the color intensity is proportional to the DNA concentration
• Fehling's Test


  • Principle: The aldehyde group of sugar is oxidized by complexed copper iron to form acid
  • Chemical reaction: Red precipitate - positive result for aldehydes
• Bial's Test


  Principle & Chemical reaction: Under hydrolysis, pentosans are hydrolyzed into pentoses; pentoses are dehydrated to yield furfural then condenses with orcinol to form blue-green precipitate
• Test for Purine Bases


  • Principle & Chemical reaction: Test for purines require both NH4OH (Ammonium hydroxide) and AgNO3 (Silver Nitrate)
  • Hydrolysis of N-β-glycosidic bonds between purine bases and ribose or deoxyribose results in a release of purine bases (Adenine and Guanine) caused by NH4OH
• Test for Phosphate


  Principle and Chemical reaction: Phosphate ions react with Ammonium molybdate in acid solution wielding yellow complex which, by the action of an alkaline buffer, is reduced to blue molybdenum that is colorimetric measured