Chem167_L17_May30

Normal mechanism peptide chain peptide chain d ala oh

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Unformatted text preview: sdar • Used for the treatment of malaria H3C N NH 2 N Cl NH 2 Pyrimethamine 1. Cell Wall Biosynthesis β- Lactams Growing cell wall . . . . . . . ...... .. .. .. . . .. . . .. . .. . . . . . . ........ . Vancomycin Cross- linking Bacitracin Cell membrane Cytoplasm . . . . Transglycosida5on Gly NAG Carrier lipid L- Ala D- Glu L- Lys NAM L- Ala Amino acid D- Ala Cycloserine D- Ala- D- Ala • Building block par5ally constructed in cytoplasm • Constructed from 2 sugars (NAM, NAG) and a pep5de chain • Transported across cell membrane and completed • Linked to growing cell wall by enzyme (transglycosida5on) • Final cross- linking reac5on catalysed by transpep5dase enzymes PENICILLINS • AnKbacterial agents which inhibit bacterial cell wall synthesis • Discovered by Fleming from a fungal colony (1928) • Shown to be non toxic and anKbacterial • Isolated and purified by Florey and Chain (1938) • First successful clinical trial (1941) • Produced by large scale fermentaKon (1944) • Structure established by X- ray crystallography (1945) • Full synthesis developed by Sheehan (1957) • IsolaKon of 6- APA by Beechams (1958- 60) - development of semi- syntheKc penicillins • Discovery of clavulanic acid and β- lactamase inhibitors Beta lactam an5bio5cs Broad class of anKbioKcs Agents that contain a beta- lactam nucleus Includes penicillin (1) derivaKves, cephalosporins (2), monobactams, & carbapenems Mechanism of acKon • Penicillins inhibit a bacterial enzyme called the transpepKdase enzyme which is involved in the synthesis of the bacterial cell wall • The β- lactam ring is involved in the mechanism of inhibiKon • Penicillin becomes covalently linked to the enzyme’s acKve site leading to irreversible inhibiKon O C HH N S R N Nu O H Me Me O Enz C CO2H HH N R...
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This note was uploaded on 01/15/2014 for the course CHEM 167 taught by Professor Amaro during the Winter '13 term at UCSD.

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