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Biochemistry Lab. Protein Purity Assessment and Identification. Coomassie Staining. How does Coomassie interact with proteins?. Coomassie Staining. Benefits. Limitations. Western Blotting. Transfer – Block Apply Primary Antibody Apply Secondary Antibody. Western Blots.
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Biochemistry Lab Protein Purity Assessment and Identification
Coomassie Staining How does Coomassie interact with proteins?
Coomassie Staining Benefits Limitations
Western Blotting Transfer – Block Apply Primary Antibody Apply Secondary Antibody
Western Blots Western Blot Coomassie Stained Benefits Limitations
Soft Ionization Techniques Matrix Assisted Laser Desorption Ionization (MALDI) Electrospray Ionization (ESI) • Aqueous sample introduced to metal capillary • High voltage (2000-4000 V) applied • Released to vacuum • Desolvation of aerosol leaving highly charged ions • Aqueous sample is cocrystallized on a metal surface with a Matrix • Intense Laser beam is directed toward sample/matrix mixture - desorption • Matrix absorbs the energy and is ionized • Some of the charge is transferred to the analyte
MALDI Matrix α-cyano-4-hydroxycinnamic acid (CCA) 2,6-dihydroxyacetophenone (DHAP) SinapicAcid (SA)
Separation Techniques Quadrupole Flight Tube • Four rods are arranged opposite each other and connected electronically • Voltage applied to each rod is carefully regulated • The trajectory of a charged particle is influenced by the electric field • Molecules separate by the time it takes for them to travel from the ion source to the detector • Resolution is dependent on tube length (limits resolving power) • Reflectron enhances the resolution
Ideal Pairs ESI-QMS MALDI-TOF MS
In lab this week • Run and stain (coomassie) the gels you prepared last week • Use Fractions 1-9 and a MW ladder • MALDI-ToF MS of your fractions SinapicAcid (SA)