Influence of urea and organic solvents on the activity of immobilizedmyo-inositol-1-phosphate synthase containing active, self-regenerating coenzyme (NAD(+)) on the same matrix.

myo-Inositol-1-phosphate synthase (EC 5.5.1.4.) from rat testes, an NAD(+)-containing enzyme that convertsD-glucose 6-phosphate to 1L-myo-inositol-1-phosphate was immobilized together with its cofactor and bovine serum albumin by crosslinking with glutaraldehyde at pH 4.5. The cofactor is reduced and reoxidized during the reaction cycle, thus forming a self-regenerating system with respect to the cofactor. The behavior of this immobilized enzyme/cofactor system in presence of organic solvents and urea and the activating effect of these compounds on the enzymatic activity were studied and discussed in the paper.