Protein Funciton Flashcards
What does protein function depend on?
Protein function depends on the structure of the protein–the amino acid composition and location
What are the 5 common protein functions?
- Metabolism
- Structure
- Transport
- Cell Signaling
- Genomic Caretakers
What are Ligands?
Small molecules bound by macromolecules which are specifically bound to protein binding sites
Where are Ligands bound?
Protein binding sites
What binds weakly with ligands?
cofactors and coenzymes
What is often coupled with ligand binding?
Conformation changes–Induced fit
What is Allostery?
When the conformational change in one subunit of a multi-subunit protein affects other subunits
How are Ligand binding and Allostery related?
Ligand binding often induces conformational changes in a subunit of a protein, these changes then cause allostery by effecting other subunits of the same protein
What types of intermolecular forces are likely to be involved in binding a cofactor/coenzyme ligand?
Covalent Bonds, Ionic bonds and Hydrogen bonds
What type of interactions occur between ligands and cofactors or coenzymes?
Weak interactions including hydrophobic interactions, ionic bonds and hydrogen bonds
What type of interactions occur between ligands and prosthetic groups?
Strong interactions including covalent bonding
What are the two hypotheses on how enzymes work?
Induced fit and complementary hypotheses
What is the complementary hypothesis?
“lock and key” model that assumes the ligand is the exact conformation needed with size, shape, charge, ionic nature and hydrophobicity
What is the Induced Fit hypothesis?
Both the protein and the ligand change their conformations to be a perfect fit
What is the equilibrium constant equation with regards to protein, ligand and protein-ligand concentrations at equilibrium? The dissociation constant?
K=[PL]/[P][L]
Kd=[P][L]/[PL]
