Penicillinase

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Penicillinase \Pen`i*cil"lin*ase\, n. (Bioch.)
     An enzyme which destroys the antibacterial activity of
     penicillin by hydrolyzing the amide bond in the beta-lactam
     ring. Many penicillinases are known, and are produced by a
     wide variety of bacteria. The production of penicillinase is
     one of the mechanisms by which bacteria may become resistant


     to penicillins. Penicillinase production in various bacterial
     species may be induced, i.e., it may occur only when
     stimulated by the presence of penicillin in the culture
     medium, or it may be constitutive, i.e., it may occur
     whenever the cells are producing protein. Molecular weights
     of the various penicillinases tend to cluster near 50,000.
     [PJC]

From WordNet (r) 2.0 [wn]:

  penicillinase
       n : enzyme produced by certain bacteria that inactivates
           penicillin and results in resistance to that antibiotic
           [syn: {beta-lactamase}]