Analysis of Proteins and Peptides - Biochemistry - Lecture Slides, Slides of Biochemistry

Download Analysis of Proteins and Peptides - Biochemistry - Lecture Slides and more Slides Biochemistry in PDF only on Docsity! Analysis of Proteins and Peptides • Amino acid composition • Molecular weight • Isoelectric point • Subunit structure • Prosthetic groups • Solubility • Biological activity Docsity.com Rule: Before a protein can be analyzed, it must first be isolated in a pure state, i.e., purified Rule: Protein purification means separating the protein of interest from other proteins and components Separation Strategies Protein from salt and small ions Protein from other proteins Protein from H2O Docsity.com Principle of Gel Filtration Penetrating the beads slows the migration rate of the smaller particles Docsity.com Protein from Protein Rule: Protein-Protein separations is based on differences in physical properties of the proteins Size or molecular weight Charge at a given pH (isoelectric point) Unique structural features Major: Minor: Solubility in water, salt solutions, or organic solvents Rule: All effective methods for separation of proteins employ the techniques of CHROMATOGRAPHY Docsity.com Chromatography: (lit., separation by color) Mobile phase Stationary phase Types: Column chromatography - gravity or pump driven Electrophoresis - driven by electric current Medium: Porous gels (size exclusion) Charged resins (charge affinity) Gas-liquid (hydrophobic interactions) Affinity resins (group recognition) Moving force Opposing force Paper (no longer in use) Osmotic movement Docsity.com CHARACTERIZATION MOLECULAR MASS Kilodaltons MOLECULAR WEIGHT No Units TRUE Molecular Weight RELATIVE Molecular Weight Sedimentation Analysis SDS (Sodium dodecylsulfate) electrophoresis Gel Filtration (MR) Docsity.com Protein Solution TCA Precipitation White Precipitate Signifies Protein TCA will remove protein from a solution Docsity.com CHARGE PROPERTIES OH H+ Docsity.com