Chapter 5

One of the reasons the primary structure is important for a protein is that it determines the the molecule adopts in aqueous solutions. A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

If the cDNA for a protein has been cloned, it may be possible to obtain large quantities of the protein by........in bacteria A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

To help prevent denaturation of proteins in solution, steps are taken to avoid and adsorption to surfaces. A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

Molecules that contain a(n) are capable of absorbing light. A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

If antibodies to the protein being assayed are available, a(n) can be carried out. A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

In general, proteins are least soluble in water when the pH is close to the A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

......chromatography is a method of fractionating a protein mixture according to differences in polarity. A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

In order for DEAE to act as an anion exchanger, it must have a A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

In chromatography, a protein mixture must be applied to the column at a low pH so that the proteins will have a net positive charge and bind to the column. A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

In SDS-PAGE, disulfide-linked polypeptides can be separated after reacting the protein first with . A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

Either dansyl chloride or Edman's reagent can be used to identify the of a proteinA) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

The endoprotease cleaves polypeptides on the C-terminal side of certain bulky hydrophobic amino acid residues. A) electrophoresis B) hydrophobic interaction C) enzyme-linked immunosorbent assay D) three-dimensional shape E) N-terminal amino acid F) negative charge G) nucleases H) chromophore I) foaming J) high level expression K) 2-mercaptoethanol L) positive charge M) cation exchange N) pI O) chymotrypsin P) C-terminal amino acid Q) Sodium dodecyl sulfate

Proteins are synthesized in vivo by the translation of

Since there are 20 standard amino acids, the number of possible linear polypeptides of length N can be expressed as:

Natural proteins most commonly contain linear polypeptides between 100 and 1000 residues in length. One of the reasons polypeptides outside this range may be disfavored is that

The vast majority of polypeptides contain between amino acid residues.

Which of the following has the most dramatic influe nce on the characteristics of an individual protein?

Which statement about insulin is correct?

A fast and common method for determining the protein concentration in column effluent is

The salting in of proteins can be explained by:

The quantitation of proteins due to their absorbance at ~280 nm (UV region) is due to the large absorbtivity of the amino acids.

Which of the following ‘assays’ would be most specific for a particular protein?

An enzyme-linked immunosorbent assay requires

ELISA is an example of a(n):

You are purifying a nuclease by affinity chromatography. To determine which fractions contain the protein of interest, you test samples of all fractions for their ability to break down DNA. This is an example of

A radioimmunoassay requires

Which physical characteristic is not commonly used in protein separation?

Adding additional salt to a protein solution can cause:

A first step in purifying a protein that was initially associated with fatty substances would be

The acronym HPLC stands for

A technique that can be used to separate proteins based primarily on the presence of non-polar residues on their surface is called

A technique that can be used to separate proteins based primarily on their pI is called

Which of the following amino acids would be last to elute at pH 8.0 from an anion- exchange column?

Which of the following amino acids would be first to elute at pH 8.0 from an anion- exchange column?

What can be done to increase the rate at which a protein of interest moves down an ion-exchange chromatography column?

Hydrophobic interaction chromatography can be used to separate proteins based on differences in

You are trying to separate five proteins, which are listed below, by gel filtration chromatography. Which of the proteins will elute first from the column?

SDS-PAGE separates proteins primarily due to differences in

Which of these techniques is used to separate proteins mainly based on mass?

Which of these techniques uses antibodies to detect very small amounts of specific proteins following separation by SDS-PAGE.

Disulfide bonds can be cleaved using

Which of these reagents is commonly used to determine the number of polypeptides in a protein?

Enzymes that hydrolyze the internal peptide bonds (not the peptide bonds of the terminal amino acids) of a protein are classified as

Which of the following substances cannot be used to cleave peptide bonds in polypeptides?

Which of these are commonly used to cleave peptide bonds in polypeptides?

Edman degradation can be used to

Although a protein’s primary sequence can be inferred from the nucleotide sequence, modifications such as can be determined most easily by tandem mass spectrometry followed by protein database searching.

The positive charge on proteins in electrospray ionization mass spectrometry is the result of

has emerged as a technique for protein sequencing.

Protein sequences are customarily ‘reconstructed’ from sequenced fragments because

You have purified a new peptide hormone. To determine its amino acid sequence you have digested the polypeptide with trypsin and in a separate reaction you have cleaved the polypeptide with cyanogen bromide. Cleavage with trypsin yielded 5 peptides that were sequenced by Edman degradation as shown in the following.

1. Ser─Leu
2. Asp─Val─Arg
3. Val─Met─Glu─Lys
4. Ser─Gln─Met─His─Lys
5. Ile─Phe─Met─Leu─Cys─Arg Cleavage with cyanogen bromide yielded 4 peptides that were sequenced by Edman degradation:
6. His─Lys─Ser─Leu
7. Asp─Val─Arg─Val─Met
8. Glu─Lys─Ile─Phe─Met
9. Leu─Cys─Arg─Ser─Gln─Met Determine the identity of the N-terminal amino acid after reconstructing the intact protein.

In two homologous proteins, which residue is most likely to replace a Glu residue as a conservative substitution?

A phylogenetic tree depicts of proteins.

A protein that has had few changes in its amino acid sequence over evolutionary history is labeled

Paralogous genes are

A fast way for nature to generate new proteins is:

is an example of a very slowly evolving protein.

Proteins are often constructed from multiple segments of 40-200 amino acid residues, commonly called