Adsorption and stabilization of yeast hexokinase

It was found that hexokinase catalyzes the phosphorylation of glucose; the second substrate-adenosine triphosphoric acid (ATP)-is a donor of phosphory l groups, while its active subunit yields less active dimers. The enzyme is extremely unstable due to the conformational lability of its two domains a nd the existence of readily oxidizable SH groups. It was shown that the num ber of SH groups is doubled during the thermal inactivation of the enzyme a nd that glucose stabilizes the soluble and immobilized forms of hexokinase. A mechanism of thermal inactivation was suggested, and the corresponding k inetic constants were calculated.