Definition of "penicillinase" []

• Any of various enzymes that are produced by certain bacteria, including most strains of staphylococci, and that hydrolyze and inactivate penicillin. They are used in medicine to treat allergic reactions to penicillin. Also called beta-lactamase. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "An example would be the bacteria that secrete penicillinase, which is an enzyme that destroys penicillin."
• "Recall that Axe did not work with the native TEM-1 penicillinase, but rather with a variant that had a lower activity."
• "The object of interest was the so-called large domain of the TEM-1 penicillinase, an enzyme that breaks down antibiotics related to penicillin."