Protein Assays & Ion Exchange

What are the 5 protein assays

Non-colorimetric
Biuret assay
Lowry assay
BCA assay
Bradford assay

Which of the 5 protein assays demonstrate LOW protein-protein variability

Biuret

What are key interferences for Non-colorimetric assays

Presence of nucleic acids

Which of the assays are good for determining presence of aromatics

Non-colorimetric (UV) assay

Which assay has Cu2+ complexation with peptide backbone bonds in alkaline medium

Biuret assay

What assay is a biuret followed reaction, time-critical 2 step procedure

Lowry assay

BCA is short for?

Bicinchonininc assay

Which assay uses Coomassie Brilliant Blue G-250 dye binding to basic/aromatic residues

Bradford assay

Define the interferences exhibited by each assay
Non-Colorimetric (UV)
Biuret
Lowry
BCA
Bradford

Nucleic acids
Ammonium Salts
Detergents (onSDS)
Reducing agents
Detergents (SDS)

What do you call the resin whose stationary phase contains negatively charged functional groups.

Cation exchange resin

What do you call the resin whose stationary phase contains positively charged functional groups.

Anion exchange resin

Give an example of anion exchange resin

Amberlite IRA-400 containing Quaternary Ammonium groups

Give an example of cation exchange resin

Dowex 50-W8 or Amberlite IR-120 containing Sulfonic Acid groups

Differentiate High-variability and Low-variability

High variability: Specific amino acid side chains
Low variability: Peptide backbone / universal bonds

Detection wavelength of Non-colorimetric (UV)

280nm

Detection wavelength of Biuret assay

540nm

Detection wavelength of Lowry assay

660-750nm

Detection wavelength of BCA assay

562nm

Detection wavelength of Bradford assay

595nm