Biochemistry
BIOCHEMISTRY REVSION
PROTIEN
Question (1): Define and distinguish primary structure, secondary and tertiary structures of proteins.
Protein Structures:
Primary structure
Primary structure of protein is its unique sequence of amino acids forming its polypeptide chain.
The primary structure of a protein is starting from the amino-terminal (N) end to the carboxyl-terminal (C).
Secondary structure
Most proteins have segments of their polypeptide chain repeatedly coiled of folded in patterns.
These coiled & folded referred as secondary structure. types of secondary structure : α-helix Rigid, rod like structure when a polypeptides chain twists into a right-handed helical conformation.
.
β-pleated sheet
Form when two or more polypeptide chain segments line up side by side.. β-pleated sheet stabilized by hydrogen bonds form between the polypeptide backbone N-H and carbonyl groups of adjacent chains.
Tertiary structure
Three-dimensional structure of a single protein molecules.
The α-helices and β-pleated sheets are folded into compact globule.
Protein folding occurs as consequence of interactions between the side chains in their primary structure.
It has several interactions that stabilize tertiary structure:
Hydrophobic interactions
Electrostatic interactions
Hydrogen bonds
Covalent bond
Question (2): Describe the process of protein denaturation. What conditions cause denaturation?
The process of protein structure disruption is called denaturation; when a protein is denatured, the secondary and tertiary structures are altered but the peptide bonds of the primary structure between the amino acids are left intact. Since all structural levels of the protein determine its function, the denatured protein can no longer perform its function once it has been denatured.
The conditions that cause denaturation :
Strong acid or base
Organic solvents
Detergents
Reducing agents.
Heavy metal
Temperature change.
Mechanical stress
PROTIEN
Question (1): Define and distinguish primary structure, secondary and tertiary structures of proteins.
Protein Structures:
Primary structure
Primary structure of protein is its unique sequence of amino acids forming its polypeptide chain.
The primary structure of a protein is starting from the amino-terminal (N) end to the carboxyl-terminal (C).
Secondary structure
Most proteins have segments of their polypeptide chain repeatedly coiled of folded in patterns.
These coiled & folded referred as secondary structure. types of secondary structure : α-helix Rigid, rod like structure when a polypeptides chain twists into a right-handed helical conformation.
.
β-pleated sheet
Form when two or more polypeptide chain segments line up side by side.. β-pleated sheet stabilized by hydrogen bonds form between the polypeptide backbone N-H and carbonyl groups of adjacent chains.
Tertiary structure
Three-dimensional structure of a single protein molecules.
The α-helices and β-pleated sheets are folded into compact globule.
Protein folding occurs as consequence of interactions between the side chains in their primary structure.
It has several interactions that stabilize tertiary structure:
Hydrophobic interactions
Electrostatic interactions
Hydrogen bonds
Covalent bond
Question (2): Describe the process of protein denaturation. What conditions cause denaturation?
The process of protein structure disruption is called denaturation; when a protein is denatured, the secondary and tertiary structures are altered but the peptide bonds of the primary structure between the amino acids are left intact. Since all structural levels of the protein determine its function, the denatured protein can no longer perform its function once it has been denatured.
The conditions that cause denaturation :
Strong acid or base
Organic solvents
Detergents
Reducing agents.
Heavy metal
Temperature change.
Mechanical stress