Out of the following given choices;
In allosteric inhibition, a regulatory molecule binds to a
location other than the active site, resulting in a change in enzyme shape that
allows the active site to bind substrate.
In allosteric activation, a regulatory molecule binds to a
location other than the active site, resulting in a change in enzyme shape that
allows the active site to bind substrate.
In allosteric inhibition, a regulatory molecule binds to the
active site, blocking substrate binding.
In allosteric activation, a regulatory molecule binds to the
active site, allowing substrate binding.
The answer is B. When an effector molecule binds to an
allosteric site, the enzyme changes conformation
causing the enzyme to have a high affinity
for its ligand at the active site. A good
example to explain allosteric regulation is hemoglobin
(which is not an enzyme though). The
subunits of the hemoglobin have
allosteric effects on each other. When oxygen
binds to one subunit, its conformation change
causing the subunit to bind to the allosteric
site of adjacent subunits. This subsequently causes the other subunits to have
more affinity for oxygen in their oxygen-binding
active sites.
