al·lo·ste·ric en·zyme
an enzyme that exhibits the property of allosterism.
Farlex Partner Medical Dictionary © Farlex 2012
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Fig. 25 Allosteric enzyme . Active (a) and inactive (b) forms.
allosteric enzyme
a type of enzyme which has two alternative forms: one active with a functional BINDING SITE, the other inactive where the binding site has been altered in shape so as to become non-reactive. Such enzymes have a QUATERNARY PROTEIN STRUCTURE which becomes changed by the addition of a ‘modulator’ molecule producing the inactive shape, such a process resulting in NONCOMPETITIVE INHIBITION.Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005