Biochemistry Review & Bioisosterism Flashcards
Which amino acids are nonpolar?
Alanine, Valine, Leucine, Isoleucine, and Proline
Which amino acids have an aromatic side chain?
Phenylalanine, Tyrosine, and Tryptophan
What amino acid has an indole ring in it’s side change?
Tyrptophan
Which amino acids have sulfur in the side chain?
Cysteine and Methionine
What amino acids have a hydroxyl group in the side chain?
Serine and Threonine
Which amino acids are polar and uncharged?
Serine, Threonine, Gluatmine, Aspargine
Which amino acids are acidic and what is their charge?
Aspartic Acid and Glutamic Acid
negative
Which amino acids are basic and what is their charge?
Lysine, Arginine, and Histidine
positive
What is special about hisitidine and its role in acid-base catalysis?
It has an imidazole ring that can accept a proton or donate a proton
What is a Bioiostere?
Compounds that possess near equal molecular shapes and volumes, approximately the same distribution of electrons.
Exhibit similar physical properties such as hydrophobicity.
Produce biological properties that are related to each other.
What are the advantages of bioisoteric replacement?
May improve pharmacokinetic properties
Can improve the pharmacological actions of the drug
May help to get rid of unwanted side effects of the drug
How many valence electrons does C, N, and O have?
C - 4
N - 5
O - 6
What does Grimm: Hydride displacement law say?
It accounts for groups with similar valence electron configurations but different numbers of atoms. C N=CH O=NH=CH2 F=OH=NH2=CH3 NE=FH=OH2=NH3
What does Hingsberg Ring equivalents mean?
Aromatic ring systems may be interchangeable. Benzene = thiophene=pyridine
What are examples of classical bioisosteres?
A. Monovalent atoms and groups B. Divalent atoms and groups C. Trivalent atoms and groups D. Tetrasubstituted atoms E. Ring equivalents
What are exampels of nonclassical bioisosteres?
A. Exchangeable Groups
B. Rings versus noncyclic structure
What are monovalent bioisoteres?
F=H OH=NH2 F=OH=NH2 or CH3 for H SH=OH Cl=Br=CF3
What are divalent bioisosteres?
C=S, C=O, C=NH, C=C
What are the differences between sildenafil and vardenafil?
Sildenafil
Bioavailability 38%-40%
Onset of Action
What is a nonclassical bioisostere?
Atoms or functional groups that do not have similar valence electron configurations and number of atoms(but may display similar biological activities).
What is Isoproterenol and Soterenol?
A nonclassical bioisotere. Non selective beta agonist. Bioisosteric replacement of m-OH of isoproterenol with a sulfonamide group. pKa values are almost equal. Similar hydrogen binding potential.
Making molecular modifications (of the tetrazole) in attempt to improve receptor binding and lipid solubility for losartan is an example of?
Nonclassical Bioisoteres. The lower the IC50 the better solubility.
Sulfydryls(Captopril) and Dicarboxylates(Lisinopril, Enalapril) are examples of what type of bioisosteres?
Nonclassical - exchangeable groups
ACE inhibitors
Estradiol and its noncyclic analogs are examples of what type of bioisosteres?
Ring versus noncyclic structure. Trans is same potency. Cis is 1/14 potency.
Sumatriptian(Imitrex) and Naratriptan(Amerge) are examples of what type of bioisosteres?
Nonclassical Bioisoteres - Ring versus noncyclic structure.
Slective agonists for serotonin. Provides relief from migraine.
What are the drug receptor interactions?
Covalent Bond (strongest)
Ionic Bond
Hydrogen Bond
Hydrophobic Interactions
Why are covalent bonds irreversible?
Receptor’s are destroyed by endocytosis and chemical destruction.
What is an example of covalent bonding to a receptor?
Blockade of alpha adrenoceptors(treatment of tumor in adrenal medulla) by phenoxybenzamine.
What is an ionic bond?
Two atoms are attracted to each other by electrostatic forces.
What is clavulanic acid?
A potent inhibitor of bacterial beta-lactamas by covalent bonds
What is beta lactamase?
Enzyme hydrolyze beta-lactams, such as the penicillin antibiotics
What enzyme does atorvastatin interact with?
HMG-CoA reductase by hydrophobic interactions
What enzyme does captopril bind?
ACE by ionic interactions, hydrogen binding, and hydrophobic pockets.
What does Fenoprofen interact with?
COX-1