Halophilic enzymes purification

A very interesting application of affinity chromatography to the purification of halophilic enzymes was reported by Sundquist and Fahey (1988). These authors have purified the enzymes bis-y-glu-tamylcysteine reductase and dihydrolipoamide dehydrogenase from H. halohium using immobilized metal ion affinity chromatography in high-salt buffers. 

In 1964, Anraku (2, S) reported the isolation of an enzyme from Escherichia coli B which hydrolyzed ribonudeoside 2, 3 -cyclic phosphates. Enzyme fractions representing a 900-fold purification also possessed 3 -nucleotidase activity. Similar activities have subsequently been purified from Proteus mirabilis (4, 5), halophilic Vibrio algino-lyticus (6, 7), Bacillus subtilis (8), and various Enterobacteriaceae, specifically, Shigella sonnei, Salmonella heidelberg, Serratia marcescens, Proteus vulgaris (9), and others (10). The enzyme from each organism is strikingly similar, but some differences are apparent. 

The existing purification procedures fall into two groups the non-halophilic approach and the halophilic approach. In the first, at certain stages in the purification procedure, the salt concentration is reduced and techniques that are suitable to low salt concentrations are applied. Inactivation in these conditions can be overcome partially either by protecting the native enzyme with its substrate or cofactors... 

---