HW6

1.  Problem 52, Modular biochemistry chapter.
 
 
 
 
 

2.  Cysteine has pKa's of 1.92, 10.78 and a side chain pKa of 8.33.  Draw the structures--to include all bonds and charges--of the three most prevalent forms at physiological plasma pH.
 
 
 
 
 
 
 
 
 
 

3.  Show why blood is red by:

    a.  Drawing the electron configuration for the Fe (III) ion.
 

    b.  Illustrating how the d electron energy levels change as the iron ion is put into a hexaligand octahedral environment.
 
 
 
 
 
 

    c.  Drawing a structure that shows how iron is coordinated in blood and that shows the six ligands.
 
 
 
 
 
 

    d. Showing the specific electronic transitions involved and explaining why this results in blood being red.
 
 
 
 
 
 
 

4.  Breast cancer occurs approximately 100 times more frequently in women than men; current thinking attributes this difference to the higher levels of estrogen found in females.  One recent research development focuses on the development of a zinc ligand molecule as a therapeutic agent to treat breast cancer.

a.  Outline the molecular mechanism of action by which estrogen molecules could plausibly and possibly cause cancer. 
 
 
 
 
 
 
 
 

b.  What are the specific molecular targets of current medicines being given to treat breast cancer.
 
 
 
 
 

c.  Clearly explain the expected mechanism of action for these potential "zinc ligand drugs."
 
 
 
 
 

d.  Outline the two main criteria that would have to be scientifically demonstrated before these new drugs could gain FDA approval.  Then outline the testing steps required to gain this approval within the U.S. and discuss the purpose of each of these testing phases.  
 


 
 
 
 
 
 
 

5.  New heart medication drugs are being developed to target inflammation by lowering the levels of C reactive protein (CRP).  Recent studies have clearly shown an association between CRP levels and the probability of heart attacks. Identify one of the approaches drug companies are testing to reduce CRP levels.
 
 
 

  
 

6.  Prednisone and cortisol are corticosteroids used to treat inflammation.  For poison ivy, cortisone cream is a common treatment, while orally administered prednisone is also used in extreme cases.  Cortisone, primarily a mineralcorticoid, cannot be taken internally; while prednisone, primarily a glucocorticoid can be taken internally.  Compare the structures of the three corticosteroids shown on the handout and identify the different structure molecular features that could possibly account for differences in mineralcorticoid and glucocorticoid activity respectively.