36
Chapter 2
Table 2.7 Some commonly used antibiotics, their use and their production host.
Antibiotic
Tvoe of comDound’
Tvoical use
Production organism
Penicillins
2
P-lactam
Bacterial infections
Pénicillium chrysogenum
Cephalosporins
P-lactam
Gram positive and Gram negative
Acremonium chrysogenum
Streptomyces
Clavulanic acid
P-lactam
P-Lactam resistant infections
3
Nystatin
Erythromycin
Tetracyclin
polyketide
polyketide
Topical, fungal infections
Streptomyces noursei
Bacitracin
polypeptide
Animal treatment
Bacillus Ucheniformis
Vancomycin
Fusidic acid
glycopeptide
MRSA infections
4
ToDical. Gram positive
1
Classification of natural products is very complicated, and the type of compound is only an indication of whether the
compounds are of similar nature.
" Penicillin is a common name for a very broad group of compounds. Most penicillins are produced semi-synthetically
from penicillin V or penicillin G (see text), and the most commonly used penicillins are amoxicillin and ampicillin.
1
Clavulanic acid is not an antibiotic in itself, but it is a P-lactamase inhibitor and may together with other P-lactams be
used to treat P-lactam resistant infections.
4 MRSA - Methicillin Resistant
Staphylococcus aureus,
a Gram positive bacteria often encountered in hospital
infections.
w>r---- COCH^V*
OOGH
OOCH
COCH
L-a-amkWMlIpicacldCystairM L-Vallnt
I ACVS
00№
0
o T lt5
LLOACV
COCH
1 IPN S
«OC
-,------
O " T
COCH o
Cephamyci
biosynthesi
HDDC
Streptomyces clavullgerus
fc
O
I
COCH o
r"^ t^ 'T -rs']
SH.
O pA i-fA cyn
Expandas»
_ _ _
DAC Syn th ase
OOCH
W.
Wi
» il
O T
n^A ^CH
0
OOCH
bop«ntcilllnN
1 A T
6
-A* I
0001
O "
COCH
Panlcimn N
DAOC
COCH
DAC
COCH
Cephalospori
biosynthesi
Penicillin
Acremonlum chrysogenum
biosynthesi
0001
Pénicillium chrysogenum
Aspergillus nldulans
DAC-Acetyl
Transferase
m
o <*-N>f^ccocH.
Figure
2.8
The biosynthetic pathway of P-lactams. For the pathway leading towards penicillin the
enzymes are: 5-(L-ct.aminoadipyl)-L-cysteinyl-D-valine synthetase (ACVS); isopenicillin N synthase
(IPNS); acyl-CoA:isopenicillin N acyltransferase (AT). The step catalyzed by acyl-CoA:isopenicillin N
acyltransferase may also proceed in a two step reaction via
6
-APA, but both these reactions are also
catalyzed by AT.
In A
cremonium chrysogenum
the same enzyme carries out expansion and
hydroxylation, whereas in
Streptomyces clavuligerus
two independent enzymes carry out these reactions.
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