Chapter 5: Proteins: Primary Structure

Vocabulary flashcards covering key terms and concepts from Chapter 5 of a biochemistry lecture on protein primary structure, purification, and analysis techniques.

Three-dimensional shape

The three-dimensional shape a protein molecule adopts in aqueous solutions, determined by its primary structure.

High level expression

Producing large quantities of a protein by cloning its cDNA in bacteria.

Foaming

A technique used to prevent protein denaturation in solution by avoiding foaming and adsorption to surfaces.

Chromophore

A molecule or part of a molecule capable of absorbing light.

Enzyme-linked immunosorbent assay

An assay carried out using antibodies to the protein being tested.

pI

The pH at which a protein is least soluble in water.

Hydrophobic interaction chromatography

A method of fractionating a protein mixture according to differences in polarity.

Positive charge

An anion exchanger that must have a positive charge to function effectively.

Cation exchange chromatography

A chromatography technique where a protein mixture is applied at a low pH to ensure proteins have a net positive charge and bind to the column.

2-mercaptoethanol

A reagent used in SDS-PAGE to separate disulfide-linked polypeptides after reacting with a protein.

N-terminal amino acid

The amino acid at the beginning of a protein that can be identified using dansyl chloride or Edman's reagent.

Chymotrypsin

An endoprotease that cleaves polypeptides on the C-terminal side of bulky hydrophobic amino acid residues.

SDS-PAGE

Separates proteins primarily based on mass.

Immunoblotting

A technique that uses antibodies to detect very small amounts of specific proteins following separation by SDS-PAGE.

Endopeptidases

Enzymes that hydrolyze internal peptide bonds of a protein.

Mass spectrometry

A technique for protein sequencing.

Paralogous genes

Genes that are the result of gene duplication.

Domains

Proteins are constructed from multiple segments of 40-200 amino acid residues.