Cell wall growth mechanism

Several drugs in current medical use are mechanism-based enzyme inactivators. Eor example, the antibiotic penicillin exerts its effects by covalently reacting with an essential serine residue in the active site of glycoprotein peptidase, an enzyme that acts to cross-link the peptidoglycan chains during synthesis of bacterial cell walls (Eigure 14.17). Once cell wall synthesis is blocked, the bacterial cells are very susceptible to rupture by osmotic lysis, and bacterial growth is halted. 

Mechanism of Action A tetracycline antibacterial that inhibits bacterial protein synthesis by binding to ribosomes. Cell wall synthesis is not affected. Therapeutic Effect Prevents bacterial cell growth. Bacteriostatic. 

Although it appears probable that there is no overall loss of wall polymers, except, perhaps, in the period just preceding full fruit-maturity, and that wall growth is continuous during cell expansion, there is almost certainly a turnover of wall polysaccharides, and the making and breaking of bonds to facilitate wall expansion during the maturation of fruits. The subject of the possible mechanism by which this wall expansion occurs is discussed in the Section that follows. 

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