Hexokinase groups

Mg-" Alcohol dehydrogenase Hexokinase 5 -Deoxyadenosylcobalamin (vitamin Big) H atoms and alkyl groups Me thy Im alony 1-CoA mutase... 

Acifluorfen, synthesis of, 683 Acrolein, structure of, 697 Acrylic acid, pKa of, 756 structure of. 753 Activating group (aromatic substitution), 561 acidity and, 760 explanation of, 564-565 Activation energy, 158 magnitude of, 159 reaction rate and, 158-159 Active site (enzyme), 162-163 citrate synthase and, 1046 hexokinase and, 163... 

Enzymes are important targets for mercury [71], and sulphydryl-group-containing enzyme being more sensitive to mercuric compounds than a non sulphydryl-group-containing enzyme [72], Enzymes reported to be inhibited include phosphatases [73, 74], dehydrogenases [75,76] and hexokinases [71]. 

As bacterial transglucosidase is instrumental in the transfer of a D-glucose residue from one acceptor to another, so does yeast hexokinase 3 catalyze a transphosphorylation. The highly specific donator of a labile phosphate group is adenosine triphosphate (XX), the fermentable hexoses D-glucose, D-mannose and D-fructose functioning as acceptors. Hexokinase catalyzes the reaction... 

Figure 10.3 In the phosphoryl-transfer reaction catalysed by hexokinase, the y-phosphoryl group of ATP undergoes inversion of configuration. (From Voet and Voet, 2004. Reproduced with permission from John Wiley Sons., Inc.)...

The x-ray structure for yeast hexokinase is also available. Thus, glucose analogs are now being used to elucidate minute details of the catalytic mechanism. Recently D- lose was used in crystallographic work to show that the 6-hydro ethyl group of the natural substrate is necessary for substrate-induced closure of the active-site cleft (81 ). This induced closure, which is observed with glucose binding (82), is believed to be a part of the induced fit mechanism postulated for hexokinase (83) ... 

This reaction, which is irreversible under intracellular conditions, is catalyzed by hexokinase. Recall that kinases are enzymes that catalyze the transfer of the terminal phosphoryl group from ATP to an acceptor nucleophile (see Fig. 13-10). Kinases are a subclass of transferases (see Table 6-3). The acceptor in the case of hexokinase is a hexose, normally D-glucose, although hexokinase also catalyzes the phosphorylation of other common hexoses, such as D-fructose and D-mannose. 

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