allosteric enzyme


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al·lo·ste·ric en·zyme

an enzyme that exhibits the property of allosterism.
Farlex Partner Medical Dictionary © Farlex 2012

allosteric enzyme

An enzyme whose activity can change when certain types of effectors, called allosteric effectors, bind to a nonactive site on the enzyme.
See also: enzyme
Medical Dictionary, © 2009 Farlex and Partners
Allosteric enzymeclick for a larger image
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