Cell walls, bacterial, mucopeptides

Deoxyribonuclease (DNAase), an enzyme that degrades deoxyribonucleic acid, has been used in patients with chronic bronchitis, and found to produce favorable responses presumably by degrading the DNA, contributed by cell nuclei, to inflammatory mucus (213). Lysozyme [9001 -63-2] hydrolyzes the mucopeptides of bacterial cell walls. Accordingly, it has been used as an antibacterial agent, usually in combination with standard antibiotics. Topical apphcations are also useful in the debridement of serious bums, cellulitis, and dermal ulceration. 

Lysozyme (muramidase, mucopeptide JV-acetylmuramylhydrolase) is a widely distributed enzyme which lyses certain bacteria by hydrolysing the / (l-4)-linkage between muramic acid and N-acetylglucosamine of mucopolysaccharides of the bacterial cell wall. 

Like the other drugs discussed in this section, vancomycin acts by inhibiting biosynthesis of the bacterial cell wall, specifically the mucopeptide portion of the peptidoglycan. It is highly active against the gram-positive cocci, staphylococci and streptococci, and C difficile. 

The vancomycin antibiotics act by an intriguing mechanism [137,138]. They interfere with the transglycosylation step of the bacterial peptidoglycan biosynthesis. Vancomycin binds to mucopeptide precursor molecules of the bacterial cell wall, terminating in Lys-D-Ala-D-Ala [139] and thereby preventing the approach of the transglycosylase. 

Carbenicillin is an extended-spectrum penicillin, that inhibits mucopeptide synthesis in bacterial cell wall. It is indicated in the treatment of acute and chronic infections of the upper and lower urinary tract, prostatitis, and asymptomatic bacteriuria caused by susceptible microorganisms. 

Dicloxacillin is a penicillinase-resistant penicillin that inhibits bacterial cell-wall mucopeptide synthesis. It is indicated in the treatment of infections caused by peniciUinase-producing staphylococcal infection and in initial therapy of suspected staphylococcal infection. 

Nafcillin sodium is a penicillinase-resistant penicillin that inhibits bacterial cell wall mucopeptide synthesis. 

Arendt, a., a. Kolodziejezyk, and T. Sokolowska Synthesis of mucopeptide fragments of bacterial cell walls containing diaminopimelic add. Part IX. Synthesis of pentapeptide related to bacterial mureine fragment. Roczniki Chem. Ann. Soc. Chim. Polonorum. 48, 1921 (1974). 

Nieto M, Perkins HR (1971) The specificity of combination between ristocetins and peptides related to bacterial cell-wall mucopeptide precursors. Biochcan J 124 845—852... 

The two types of reaction by which D-amino adds may be formed in vivo are dealt with in this section. The mechanisms by which d-amino acids are incorporated into cell-wall mucopeptides and bacterial antibiotics are not well understood but will be mentioned briefly in section V.E. 

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