Mucopeptide

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. 

Pharmacology Penicillins inhibit the biosynthesis of cell wall mucopeptide. They are bactericidal against sensitive organisms when adequate concentrations are reached and most effective during the stage of active multiplication. Inadequate concentrations may produce only bacteriostatic effects. 

Inhibits synthesis of cell-wall mucopeptides (peptidoglycans). 

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. 

Cell wall Peptidoglycan (murein or mucopeptide) as component Absence of peptidoglycan... 

The principle distinguishing features of the procaryotic cell are 1) absence of internal membranes which separate the resting nucleus from the cytoplasm, and isolate the enzymatic machinery of photosynthesis and of respiration in specific organelles 2) nuclear division by fission, not by mitosis, a character possibly related to the presence of a single structure which carries all the genetic information of the cell and 3) the presence of a cell wall which contains a specific mucopeptide as its strengthening element, (p. 21 in Stanier and van Neil 1962) . 

H. R. Perkins, Specificity of combination between mucopeptide precursors and vancomycin or ristocetin, Rioc/em. J. Ill (1969), 195. 

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. 

Very recently, Czerkawski et al. (1963), studying the composition and structure of the cell wall mucopeptide of Micrococcus lysodeikticus paid special attention to the number of free basic and acidic groups present, using titration and dye-absorption methods. They found that 40 % of the 7-carboxyl groups and a similar proportion of the e-amino groups were not free. As the mucopeptide was known to be extensively cross-linked, the authors concluded that this cross-linking involves side-chain peptide bonds between lysine and glutamic acid. 

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. 

The antibiotic forms a number of hydrogen bonds to the mucopeptide precursor molecule with which it interacts. This alignment is strengthened by hydrophobic interactions between... 

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