6] Alcohol dehydrogenase coimmobilized with its coenzyme

Abstract

This chapter describes alcohol dehydrogenase coimmobilized with its coenzyme. Alcohol dehydrogenase occurs in a variety of plant and animal organisms. The most widely studied alcohol dehydrogenase, a cytoplasmic protein, is usually obtained from baker's yeast, which is also the source of the coenzyme NAD. Many enzymes, such as the dehydrogenases, require the participation of easily dissociable coenzymes; and for obvious practical and economic reasons, it is useful to be able to immobilize them side by side. Coimmobilization is, however, only successful if certain conditions are satisfied. It is important for the enzyme and coenzyme to be held in a suitable spatial arrangement and for the coenzyme to be easily regenerated during the course of reaction. The matter of regeneration of the coenzyme also has to be dealt with by positioning it suitably with respect to the enzyme. Because of these factors, the coimmobilization of enzymes and coenzymes has not always been met with complete success. In the case of alcohol dehydrogenase and its coenzyme nicotine adenine dinucleotide (NAD), the recycling of the latter has been achieved for many years and derivatives of the coenzyme with flexible side arms have been synthesized.