week 9-10 Flashcards
Protein
A protein is a polymer in which the monomer units are amino acids.
α -Amino acid
An α-amino acid is an amino acid in which the amino group and the carboxyl group
are both attached to the α-carbon atom.
standard amino acids
A standard amino acid is one of the 20 α-amino acids that are normally
present in protein.
amino acid classification
Amino acids are classified as nonpolar, polar neutral, polar basic, or polar acidic depending on the nature of the side chain (R group) present.
essential amino acids
A standard amino acid needed for protein synthesis that must be obtained from dietary sources because the human body cannot synthesize it in adequate amounts from other substances.
chirality of amino acids
Amino acids found in proteins are always left-handed (L-isomer).
zwitterion
A zwitterion is a molecule that has a positive charge on one atom and a negative charge on another atom. In neutral solution and in the solid state, amino acids exist as zwitterions. For amino acids in solution, the isoelectric point is the pH at which the amino acid exists primarily in its
zwitterion form
disulfide bond formation
The amino acid cysteine readily dimerizes; the -SH groups of two
cysteine molecules interact to form a covalent disulfide bond.
peptide bond
A peptide bond is an amide bond involving the carboxyl group of one amino acid and the amino group of another amino acid. In protein, the amino acids are linked to each other through peptide bond
primary protein structure
The primary structure of a protein is the sequence of amino acids present in the peptide chain or chains of the protein.
secondary protein structure
The secondary structure of a protein is the arrangement in space of the backbone portion of the protein. The two major types of protein secondary structure are the α- helix and the β- pleated sheet.
Tertiary Protein Structure
The tertiary structure of a protein is the overall three-dimensional
shape that results from the attractive forces among amino acid side chains (R-groups).
Quaternary Protein Structure
The quaternary structure of a protein involves the association among the peptide chains present in a multimeric protein
Protein hydrolysis
Protein hydrolysis is a chemical reaction in which peptide bonds within a protein are broken through reaction with water. Complete hydrolysis produces free amino acids.
Protein Denaturation
Protein denaturation is the partial or complete disorganization of a protein’s characteristic three-dimensional shape as a result of disruption of its secondary, tertiary, and quaternary structural interactions
Glycoproteins
are conjugated proteins that contain carbohydrates or carbohydrate derivatives in addition to amino acids. Collagen and immunoglobulins are important glycoproteins.
Lipoproteins
Glycoproteins are conjugated proteins that contain carbohydrates or carbohydrate derivatives in addition to amino acids. Collagen and immunoglobulins are important glycoproteins.
