Stabilization of soluble and immobilized horse liver alcohol dehydrogenase by adenosine 5'-monophosphate

Horse liver alcohol dehydrogenase, which catalyzes oxidoreductions for a broad spectrum of substrates of organic chemical interest, was immobilized on CNBr-activated Sepharose and on decylamine-substituted agarose. The specific activities of the immobilized enzyme preparations were compared with the free enzyme, and the apparent K(m) values of the preparations were determined for a selection of substrates. At pH 9 and 60 degrees C, soluble liver alcohol dehydrogenase was rapidly inactivated, while the enzyme immobilized on CNBr-activated Sepharose was more stable. Adenosine monophosphate (AMP), adenosine diphosphate, and adenosine diphosphoribose protected the free and immobilized alcohol dehydrogenase against heat inactivation. On storage under a variety of conditions, AMP effectively stabilized free horse liver alcohol dehydrogenase and the immobilized preparations.