Question

how the predicted structure/compartmentalization of human glucokinase may or may not fit with its function within a cell

Answer 1

Ans . Glucokinase may exist in 3 conformations :- Closed form (Active), Open form (Active) , Super - open form (Inactive).

The conformational changes between the open form and the super-open form are slower steps than the closed-open conformational change occuring during glucose phosphorylation.

Unless glucose is present, the majority of glukokinase remains in the thermodynamically favourable super-open form. When glucose binds to the super - open form, glucokinase undergoes a conformational change to open form.

After the slow transition to the open form, the enzymatic reaction is carried out by changing to closed form in the presence of ATP. After the reaction is completed , glukokinase returns to its open form in order to release glucose-6-phosphate and ADP.

Because the open form slowly equilibrates with the super-open form , a large proportion of glucokinase stays in the open form for sometime. If glucose binds to the open form during this period, glucokinase re-enters the catalytic cycle. If this does not happen, glucokinase returns to the super-open form.