Post Purification Analysis Quiz

Which of the following methods is commonly used to estimate the molecular weight of a purified protein?

• Western Blot

• Bradford Assay

• SDS-PAGE

• Isoelectric Focusing

What is the main purpose of performing Western blotting after SDS-PAGE?

• To separate proteins by pI

• To confirm protein purity

• To detect a specific protein using antibodies

• To determine protein solubility

Which technique would you use to separate proteins based on their isoelectric point (pI)?

• SDS-PAGE

• UV absorbance at 280 nm

• Isoelectric Focusing (IEF)

• Gel Filtration

What is the main principle behind Native PAGE?

• Separation by molecular weight

• Separation by charge and conformation

• Separation by affinity to ligands

• Denaturation of proteins before separation

Which of the following assays requires no reagents and can directly measure protein concentration?

• Lowry Assay

• Bradford Assay

• UV Absorbance at 280 nm

• BCA Assay

In SDS-PAGE, what is the role of SDS?

• Stabilizes pH

• Reduces proteins

• Gives uniform negative charge to proteins

• Stains proteins for visualization

Why is Coomassie Brilliant Blue used after running an SDS-PAGE gel?

• To denature proteins

• To detect antibody binding

• To visualize protein bands

• To reduce disulfide bonds

Which of the following is a highly specific method for detecting target proteins post-purification?

• Isoelectric Focusing

• Native PAGE

• Western Blot

• UV 280 nm

Which factor does not affect protein migration in Native PAGE?

• Protein shape

• Net charge

• Protein folding

• SDS binding

Which of the following is used to assess the enzymatic activity of a purified protein?

• SDS-PAGE

• Protein assay

• Enzyme activity assay

• Isoelectric focusing