hexokinase hydrolyzes ATP to ADP?

Question

How does hexokinase hydrolyzes ATP to ADP?

Answer 1

Hexokinase, from a point of view, hydrolyzes ATP. From another point of view, it "transfers" the phosphate from ATP to glucose (hexoses) thus generating ADP and a hexose-phosphate.

It is actually referred to as a phosphotransferase.

Hexokinase is an important glycolytic enzyme and irreversible in its catalysis. As the breaking of ATP is exothermic, the formation of hexosephosphate can not be reversed to form a hexose and ATP.

Answer 2

A hexokinase is an enzyme that phosphorylates a six-carbon sugar, a hexose, to a hexose phosphate.They are categorized as actin fold proteins, sharing a common ATP binding site core surrounded by more variable sequences that determine substrate affinities and other properties.

The intracellular reactions mediated by hexokinases can be typified as:

Hexose-CH2OH + MgATP= → Hexose-CH2O-PO3= + MgADP- + H+

where Hexose-CH2OH represents any of several hexoses (like glucose) that contain an accessible -CH2OH moiety.


Catalytic activity : ATP + D-hexose = ADP + D-hexose 6-phosphate