Proteins And Their Primary Structure

Question 1

List Five Functions of Proteins

Answer 1

Enzymes, Hormones, Storage, Transport, Structure, Protective, Contractile, Antibodies

Question 2

What is the minimum number of residues needed for a protein to fold into its tertiary structure.

Answer 2

40

Question 3

List four physical characteristics that can be used to separate proteins.

Answer 3

Solubility
Electrical charge or polarity
Size and Shape
Affinity or Specificity

Question 4

What are three techniques used for separating proteins based on charge?

Answer 4

Ion exchange chromatography
Isoelectric focusing
Electrophoresis

Question 5

What are three techniques used for separating proteins based on size?

Answer 5

Dialysis and ultracentrifugation
Gel electrophoresis
Gel filtration (size exclusion chromatography)

Question 6

What technique is used to separate proteins based on size and charge?

Answer 6

2-D chromatography

Question 7

What technique is used to separate proteins based on specificity?

Answer 7

Affinity chromatography

Question 8

What three techniques are used to separate proteins based on polarity?

Answer 8

Paper chromatography
Reverse-phase chromatography
Hydrophobic chromatography

Question 9

What is the primary structure of a protein?

Answer 9

The particular sequence of amino acids in a protein.

Question 10

Describe Edman degradation

Answer 10

Phenylisothiocyanate labels the the N-terminal end of a peptide chain. This PTH derivative can then be released under acidic conditions, forming a new N-terminal. The process is then repeated.

Cannot be used for peptides longer than 20-30 amino acids.

Question 11

What are the advantages of Protein ID via Mass Spectrometry?

Answer 11

High specificity
High Sensitivity reduces the need for protein purification
Can ID several peptides from the protein at once (High Coverage)
Multiple proteins can be ID’d in a single analysis
Post-translational modifications and locations can be determined.