a)
Substrate compulsory
to hexokinase causes large conformational variations which forms the binding
site for ATP
and eliminates water from active site. This averts ATP
from binding in the absenteeism of the other substrate,
which would endorse hydrolysis in its place of phosphate
transfer.
b)
Opposing anabolic and
catabolic pathways have diverse enzymes that catalyze opposite irreparable
reactions. These are differentially regulated when one is stimulated
the other is reserved to guarantee that
only one pathway is efficient at a time.
