Exam 3: Amino Acids and the Primary Structures of Proteins

Proteins are treated with substances such as 2-mercaptoethanol to remove disulfide bonds before being sequenced because the disulfide bonds will interfere with the sequencing procedure.

What is the net charge on the dipeptide Arg-Pro at pH 9.0? The table below gives the pKa's of the ionizable groups on the free amino acids.

All amino acids have mirror-image pairs designated D and L.

The last common ancestor of modern organisms must have used

All 20 common amino acids exist in nature equally as both the D and L stereoisomers.

Most proteins contain an approximately equal amount of each of the standard amino acids.

Which will react with amino acids to yield derivatives that can be detected by monitoring the absorbance at 254 nm?

The isoelectric point of amino acids is the average of the values pKCOOH + pKNH₂.

Match the following to their functions. -Regulates mammalian metabolism.

How do the pKa values of an ionizable side chain compare when the amino acid is free versus when it is in a polypeptide chain?

A protein that contains more isoleucine,phenylalanine and leucine than asparagine,lysine and arginine is most likely

An amino acid named for a plant from which it was first isolated is

In the amino acid analysis the PTC-amino acid derivatives of a hydrolyzed protein are subjected to HPLC.How do you determine which amino acids are present?

Which technique is most sensitive and accurate for the determination of a protein's molecular weight?

Which is used to hydrolyze the peptide bonds of a protein to yield free amino acids?

Glycine is not a stereoisomer because

Concentrations of some proteins cannot be estimated by UV spectrophotometry because they are

Amino acids found in meteorites and near stars are

In gel electrophoresis the molecules with the highest molecular weight migrate the farthest from the starting wells.

How does one determine a tryptic fingerprint to identify a protein?