beta-lactamase

noun

be·​ta-lac·​ta·​mase ˈbā-tə-ˈlak-tə-ˌmās 

-ˌmāz

: any of various bacterial enzymes that inactivate the penicillins and cephalosporins by hydrolyzing them

When confronted with an antibiotic, a number of disease-causing bacteria will retaliate by making an enzyme called beta-lactamase …

—Diana Morgan and Terence Monmaney

Word History

Etymology

lactam, a cyclic amide (from International Scientific Vocabulary lact- + amide) + -ase

First Known Use

1963, in the meaning defined above

Medical Definition

beta-lactamase

noun

be·​ta-lac·​ta·​mase

variants also β-lactamase

-ˈlak-tə-ˌmās, -ˌmāz 

: any of various bacterial enzymes that inactivate beta-lactam antibiotics (such as penicillin and cephalosporin) by hydrolyzing them

When confronted with an antibiotic, a number of disease-causing bacteria will retaliate by making an enzyme called beta-lactamase …

—Diana Morgan and Terence Monmaney, Science

The most common mechanism of resistance to β-lactam antibiotics is the bacterial production of an enzyme called β-lactamase, which breaks one of the antibiotic's chemical bonds, changing its structure and preventing it from inhibiting the enzyme transpeptidase.

—K. C. Nicolaou et al., Scientific American

Note: Beta-lactamase was originally used only to refer to bacterial enzymes that inactivated penicillin. As additional types of beta-lactam antibiotics were introduced, other bacterial beta-lactamases were identified.

compare penicillinase