NADP-dependent isocitrate dehydrogenase from the mussel Mytilus edulis L. 1. Purification and characterisation

A purification scheme is described for NADP-dependent isocitrate dehydrogenase from the digestive gland of Mytilus edulis. The scheme incorporates three chromatographic steps: hydroxyapatite adsorption, blue-Sepharose affinity chromatography and DEAE-Sephacel ion-exchange chromatography. The subunit molecular weight of the enzyme was 45 000 (+/- 5000) by sodium dodecylsulfate gel electrophoresis. The purified enzyme was homogeneous on dodecylsulfate gels and had a specific activity of 30--50 U/mg protein.