Protein-Binding Sites & Chemical Signalling Flashcards
1
Q
Protein binding sites bound by:
A
- Electrical attractions
- Weak attractions between nonpolar regions
2
Q
Determinants of Reaction Rate
A
- Reactants concentration
- Temperature
- Activation energy
- Catalyst
3
Q
Chemical specificity
A
- Ability to bind specific ligands
- Charges and shapes must be complementary
4
Q
Signal transduction pathways
A
Sequence of events by which binding initiates a response
5
Q
Signal transduction pathways lead to change in:
A
- Permeability
- Metabolism
- Secretory activity
- Rate of proliferation
- Contraction
6
Q
- Binding of a protein to one of the sites alters the shape of the other
- A ligand that binds to regulatory site is a modulator molecule
- Cooperativity
* When a ligand binds to a functional site, it induces a change that increases affinity of other sites
A
Allosteric modulation
7
Q
- Covalent binding of charged chemical groups to some of the protein’s side chains
- Kinase - phosphorylation
- Phosphatase - dephosphorylation
A
Covalent modulation
8
Q
- Activation results in a conformational change of the receptor so it forms an open channel
- Opening increases net diffusion of ions
- Results in a change in membrane potential
A
Type A - Ligand Gated Ion Channels
9
Q
- Autophosphorylation of the receptor
- Phosphotyrosine serve as docking sites for cytoplasmic proteins
- Docking proteins activate others
A
Type B - Enzymes
10
Q
- Receptors must use a cytoplasmic kinase
- Binding of ligand leads to activation of cytoplasmic kinase
A
Type C - JAKs
11
Q
- Protein complex on cytosolic surface bound to inactive receptor
- Alpha subunits can bind GDP, which signals off and can bind GTP, which signals on
A
Type D - G Proteins
