Exam 1 (lecture 6-9/16) Flashcards
(85 cards)
List four functions of proteins
- Structural
- Movement and Localization of cells and molecules
- Ligand Binding
- Enzyme Catalysis
Structural proteins
gives cells their shape (usually fibrous)
Movement of cells and molecules proteins are broken up into:
Motor and membrane transport
Motor Proteins
cell movement, movement of chromosomes & organelles, causes change in conformations
Do motor proteins use ATP/GTP?
Yes. They use ATP/GTP hydrolysis to drive movement in one direction.
Membrane Transports
movement of molecules across the membrane, across entire membrane
Ligand
molecule bound by another proteins
Ligand Binding
protein folding creates a binding site. Ligand fits precisely into the binding site to maximize noncovalent interactions
More noncovalent interactions the more ______ to break apart
unlikely
What are the three types of protein-protein binding
- Surface-String
- Helix-Helix
- Surface-Surface
Antigen-Antibody Binding
tight, selective binding
Larger Ka
greater bonding strength (more products for assciation)
Larger Kd
not bound to eachother (lower affinty for eachother)
Equilibrium Constant
tells you if something prefers to be associated or not
if two proteins are known to bind the same ligand, this suggests….
proteins have similar structures
specificity of binding is determined by_______
a few amino acids near and within the binding site
Enzymes usually end in
-ase
Synthases
synthesize molecules in anabolic reactions by condensing two smaller molecules together
isomerases
catalyze the rearrangement of bonds within a single molecule
phosphatases
catalyze the hydrolytic removal of a phosphate group from a molecule
Pre-Steady State
ES (enzyme substrate) is just forming
Steady State
ES is almost constant, ES breaks downs and forms at the same rate
Steady State occurs when
there is enough substrate to saturate the enzyme and Vmax is achieved
K1
rate constant for formation for ES (association)
