Figure 5.

Amino acid contacts to glucose in the catalytic site of human brain hexokinase [21, 41]. Serine 603 is not shown here, but is in steric contact with the hydrogen at the 2-H of glucose, resulting in an inverse isotope effect for this position (Figure 4). The interactions of Asn656 to the 4-hydroxyl group are weak compared Asp657 and Asn683, indicated by the wavy lines.