**46. Isocitratelyase**

A four-stage purification procedure comprising ammonium sulfate precipitation and ion ex‐ change chromatography on DEAE cellulose has been elaborated for isolation of isocitrate lyase (EC 4.1.3.1) isoforms from soybean cotyledons, the isoform that migrated quickly in PAAG had a much lower affinity to isocitrate (KM - 50 M) than the slowly migrating form (KM - 16 M). The conservation of activity of the isoforms obtained depends on the presence of divalent cations (Mn2+ and Mg2+) in the medium. It is suggested to use the isoforms of iso‐ citrate lyase isolated from soybeans for the development of biosensors for biochemical and kinetic assays [50].
