Biochemistry · MU Sofia

4. Charge Properties of the Amino Acids and Proteins…

Explains how the net charge of amino acids and proteins depends on side chains, pH and solvent, and defines the isoelectric point. It then covers electrophoresis, serum protein fractions for diagnostics, SDS-PAGE and capillary electrophoresis, several chromatographic separation methods, and a short section on phenylketonuria with its phenylalanine-to-tyrosine pathway.

Inside: 11 sections · 5 labelled pictures · 15 flashcards · 9 min

Topic 4 of 70 in the MU Sofia syllabus for Biochemistry (Dental Medicine, Year 2). The free AceMed note covers it in 11 sections, about 1,306 words (9 min of reading), with 15 flashcards.

In this note

  1. Charge Properties of the Amino Acids and Proteins
  2. Electrophoresis:
  3. Electrophoretic profiles of serum proteins; role for diagnostics
  4. SDS-PAGE:
  5. Capillary Electrophoresis:
  6. Chromatographic techniques
  7. Hydrophobic interaction chromatography
  8. Gel filtration chromatography
  9. Affinity chromatography
  10. Principles of quality and quantity analysis of proteins:
  11. Phenylketonuria:

Charge Properties of the Amino Acids and Proteins

  • Electrical charge of amino acids and proteins is dependent on type of side chains, nature of solvent and pH
  • Increase of pH = positive charge decreases, Decrease of pH = positive charge increase
  • The isoelectric point refers to the pH when the molecule has net charge of 0 (the molecule is not attracted to either positive or negative charges and aggregates and precipitates out of the solution).
  • Overall charge of amino acids is determined by 3 things:
  1. 1. dependant on the side chain/ r group
  2. 2. pH
  3. 3. Nature solvent : for example aqueous solvent

Electrophoresis:

  • is the movement of charged molecules in an electric field. They move and separate in relation to their charge and molecular weight.
  • When the isoelectric point of a molecule is greater than the pH of the surrounding solution, the molecule will have a net negative charge (they then move towards the anode)
  • when the isoelectric point of a molecule is less than the pH of the surrounding solution, the molecule will have a net positive charge (they then move towards the cathode).

Continue reading free

The whole note, all 11 sections, is free with an AceMed account, with its 15 flashcards. Premium adds flashcard recall, highlights and Ask AI.

Start freeAlready a member? Open the note