Human Hexokinase I (HK) is one of four mammalian HK isozymes, consisting of a single polypeptide chain of 100 kDa. The enzyme catalyzes the first glycolytic step, i.e., the transfer of a phosphate group from ATP to glucose to yield glucose-6-phosphate (G6P).

Recombinant human brain HK was crystallized in the monoclinic P21 space group (a = 82.4 Å b=174.3 Å c=86.3 Å ß=90.5°). X-ray diffraction were collected at the ESRF synchrotron radiation facility in Grenoble at a resolution of 2.25 Å. Refinement and analysis of the structure has been carried out up to a R-factor value of 20.8% with ideal geometry. A non-catalytic binding with ATP has been found in the N-terminal domain of the protein suggesting a mechanism for mitochondrial outer membrane:enzyme association/dissociation processes

Other images: hexokinase human type I - ribbon