Upgrade to remove ads
Only $35.99/year

Lamango Study Guide

Terms in this set (36)

1. Why is a properly functioning immune system essential for a bacteriostatic agent to be effective?
That is the only way the bateriostatic agent can kill the bacteria.
2. What types of functional group on β-lactam antibiotics makes it possible for these drugs to be stable in the stomach?
● R- groups that are electron withdrawing are more stable in acids
○ electron withdrawing groups reduce the electron density on the side chain carbonyl oxygen, thus increasing acid stability

●Amino groups on the side chain along with the carboxylic acid.
3. Are you able to explain how these groups help in the acid-stability of the β-lactam bond?
1. The Beta-lactam structure is the main component of the pharmacophore. Meaning that specific sites on the Beta-lactam bond help in the acid stability.


2. The NH2 group is basic, hence it will cause neutrality, decreasing the potential for degradation in acidic medium.
4. Are you able to identify the structural modifications on β-lactam antibacterials that make them resistant to β-lactamases? Can you explain how they are able to prevent the enzyme degradation?
Strategically placed steric bulk may impede access to Beta-lactamase active sites and thus confer resistance to Beta-lactamase hydrolysis
5. Which enzyme in bacteria is inhibited by the β-lactam antibacterials? What are the other names for these enzymes?
Beta-lactam antibacterials will inhibit transamidase or transpeptidase (another name of these enzymes are PBPs). Penicillin binding proteins
6. How do the β-lactam antibacterials inhibit this enzyme? Is it reversible or irreversible inhibition? What do these two terms mean in a biochemical sense?
How:

1. Binding of drug to the PBPs (irreversibly)

2. Inhibit transpeptidation reaction (this will stop the cross-link)

3. Activation of autolytic enzymes (will cause lesions in the cell wall)

Yes, this will selectively and irreversibly inhibit the enzymes that process the developing peptidoglycan layer
7. Are you able to identify the different types of β-lactam antibacterials? Are you able to explain the differences between them to your friends?
check document
8. Are you able to describe the mechanisms of allergenicity of the β-lactam antibacterials?
● Nucleophiles in proteins conjugate with the Beta-lactams (haptens) to form antigenic conjugates that cause allergies to penicillins and related compounds

○these compounds will react with
amino group in our proteins,
making them look different to our
immune system, causing allergic
reactions

● Antigenic aggregates formed from intermolecular reactions of ampicillin amino with the Beta-lactam bonds of adjacent molecules may cause allergic reactions
9. Are you able to explain why some are more allergic than others?
● Penicillins are more allergenic than cephalosporins because the ring is small (5 carbon) and there is more ring spin on the beta lactam ring making it more reactive to proteins

● As you go up in generations of cephalosporins they become less allergenic and more broad spectrum

● carbapenems are 5 member rings that are smaller than penicillins (C is half the size of S) and thus are more allergenic than penicillins
10. Is the allergenicity related to their chemical stabilities/reactivities? If so, how?
● beta lactams react with the proteins which is nucleophilic, to form antigenic conjugates that cause allergies.

● this will make them look different to our immune system and cause an immune response, making it look foreign.

● amino group reacts with beta lactams adjacent to the other molecules to cause a large polymer
11. What kind of enzymes are the PBPs?
PBP is penicillin-binding proteins or transamidases or transpeptidase. They are enzymes that float in the cytoplasmic membrane in Gm (+) bacteria and they are kept in the periplasmic space of the Gm(-) bacteria. The function is believed to be construction and repair of the cell wall of bacteria.

● transaminase-
● Transpeptidases-
● PBPs
○ serine hydrolysis- irreversibly bind to PBP active site
12. What does transmidation mean? Can you show it using simple chemical drawings?
This is the transfer of an amide group from one compound to another
13. Which β-lactam antibacterial would react both with the PBPs and β-lactamases
● Cephalosporins kill bacteria by binding to PBPs and have Beta-lactamase activity.

● Carbapenems inactivate Beta-lactamases and kill bacteria by binding to PBPs.

● Aztreonam (a monobactam) capable of inactivating some Beta-lactamases and bind to PBPs
The below questions cover Tetracyclines, Aminoglycosides, Macrolides,
The below questions cover Tetracyclines, Aminoglycosides, Macrolides, M
14. Which group of agents inhibits the binding of aminoacyl transfer tRNA (A-site)?
● Tetracyclines bind to 30S and perhaps 50S ribosomal particles

○ When bound, it inhibits the
binding of aminoacyl transfer RNA
to the ribosome

○ A Site: Aminoacyl transfer RNA
site

○Causing a premature polypeptide
chain termination
Recommended textbook explanations

Chemistry: The Central Science

14th EditionBruce Edward Bursten, Catherine J. Murphy, H. Eugene Lemay, Matthew E. Stoltzfus, Patrick Woodward, Theodore E. Brown
7,708 explanations

Pearson Chemistry

Matta, Staley, Waterman, Wilbraham
3,743 explanations

Chemistry Matter and Change

1st EditionButhelezi, Dingrando, Hainen, Wistrom
4,873 explanations

Physical Science Concepts In Action

2nd EditionFrank, Wysession, Yancopoulos
1,490 explanations