Antibiotic Chemistry Flashcards
pharmacy year 2
What are the 6 antibacterial mechanisms of action
inhibition of bacterial cell wall synthesis
inhibition of protein synthesis
inhibition of nucleic acid transcription and replication injury to plasma membrane
inhibition of synthesis of essential metabolites
miscellaneous
what happens in antibacterial drug action
inhibition of cell wall synthesis
inhibition of nucleic acid replication and transcription injury to plasma membrane
kill bacteria by damaging their cell membranes
inhibition of protein synthesis
kill or impair the growth of bacteria by preventing them from making proteins
inhibition of synthesis of essential metabolites disrupt essential bacterial metabolic pathways
(antimetabolites)
what is our body made out of?
made out of eukaryotic cells, Muti-celled
what is bacteria body made out of?
made out of Prokaryotes : Unicellular
describe the structure of bacteria
they have a slimy capsule made of polysaccharide
there’s a cell wall in most prokaryotes
a cell wall is a structural layer, which encapsulates bacteria , and offers structural support and protection.
Filtering capabilities
what does a bacteria cell consist of?
capsule
flagella
cell wall
cell membrane
ribosome
chromosomes
nucleic region
flagellum
what’s the difference between gram positive and gram negative
gram -negative is thin
gram-positive is thick
what is B-1,4-glycosidic bonds the site of?
site of cleavage by lysozyme with a reducing end
describe the segments of NAM and NAG
Segments in a alternating pattern
Peptidoglycan
cross-linked by short, four to five amino acids long , or tetrapeptide chains, protruding from NAM subunits
what is transpeptidation
the pentapeptide chains reach out and link to chains from the neighbouring strands .
DD-transpeptidases or penicillin binding proteins highly selective
inhibition of bacterial cell wall synthesis
B-lactam antibiotics such as penicillin and cephalosoporins, have a b-lactam ring in their structure
b-lactam antibiotics are bactericidal and act by inhibiting the synthesis of the peptidoglycan layer of bacterial cell walls
give examples of penam
Amoxicillin , Benzylpenicillin , co-amoxiclav , flucloxacillin, penicillin V, Tazocin , Pivmecillinam, Temocilllin
don’t have an
give examples of cefam
cefalexin, cefixime , cefoatimne, ceftazidime, ceftriaxone , cefuroxamine, ciprofloxamine
penem
have a double bond
carbapenem
ertapamen, meropenem
monobactam
aztreonam
structure activity relationship SAR
R group may be varied with enzymes and semi-synthetic methods
EWG- N less nucleophilic bulky group - steric
hinderance of B-lactamase
b-lactam ring
b-lactam ring may be opened with OH,NH2,SHeg H2O
carboxylic acid
normally negatively charged forming salt bridge in enzyme pocket
involved in ionic interaction
with N of binding site
the smaller the ring
the more reactive
b-Lactam structures
penam, amoxicillin, cefam,,cefaların, penem, carbopenem, ertapamen, monobactam aztreonam
mechanism of action
cleavage of the D-alanyl-D-alanine bond of a peptide unit precursor acting as carbonyl donor , the release of the carbonyl -terminal D-alanine , and the formation of the acyl-enzyme
the breakdown of the acyl-enzyme intermediate and the formation of a new peptide bond between the carbonyl of the D-alanyl moiety and the amino group of another peptide unit
DD–transpeptidase mechanism
there are always key amino acids in charge of this interaction
Ser35
