Week 5 post 1

Week 5 video 1
-Receptors are proteins that bind to a small molecule, like an enzyme
-receptors act as a molecular switch, binding to molecules call ligands 
-when ligands bond to a receptor, it causes a change in the protein which makes a cellular cascade and then a response in the cell
-ligands can be in two categories. Either endogenous or exogenous
-endogenous are natural molecules that interact with the receptors within the body
-exogenous is what is dealt with in the drug industry, which are synthetic molecules
-meant to interfere with receptors to give control of cellular processes and affect the disease state
-receptors fall into categories as well
-the first superfamily is the ligand-gated ion channels large membrane bound proteins. 
-these receptors control the flow of ions across a membrane 
-this is necessary to get ions in and out of a cell, this is pretty fast
-the next super family is G-protein coupled receptors which are also membrane bound proteins
-when bound by a ligand allow a signal to go from outside to inside of a cell
-when the signal reaches the inside of a cell it releases G proteins which go into cell and make signal. This is fairly slow
-the third superfamily is the tyrosine Kinase-linked 
-these are membrane bound ligand binding causes receptor diners
-diners are two identical molecules linked 
-dimers act as enzymes
-associated with cancer
-the fourth superfamily is the nuclear receptors
-not in cell membrane, but in the cell nucleus
-control gene expression and how DNA is handled in cell
-risky to mess with because it is the the fundamental part of the cell
-ligand must enter cell
-waiter to get drug to sit on outside of cell and transmit a signal then to get into a cell

Video 2
-ligands come in 4 types
-the first is full agonists can get a full response from the receptor
-sigmoidal curve behavior 
-achieved 50% with log ec50 concentration 
-the difference between the ligand is how fast they achieve 50%. 
-another type is the partial agonists. Cannot achieve full response 
-still sigmoidal, and still has an ec50 value, but instead at a lower %
-1/2 of its potential not of max value
-antagonist ligands bind to receptor and don't cause a response
-can suppress a response by agonists 
-final ligand is the inverse agonists
-some receptors can work without a ligand, but very weak
-inverse cause it to go down to zero.
-Antagonists don't work with the constituent active receptors

Video 3
-clarks occupancy theory 
-binding=response
-Clarks equation is (E/Emax)=[L]/(Kd+[L])
-kd is an equilibrium constant that is th position dissociation of the complex
-at ec50 the Kd=Ec50 value
-the structure of a drug and how it interacts effects the activity
-binding is not always response 
-ex the constituent active receptors
-spare receptors are not need for full response

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