title: Stability of an extreme halophilic alkaline phosphatase from Halobacterium salinarium in non-conventional medium.
abstract: Alkaline p-nitrophenylphosphate phosphatase from the halophilic archaeon Halobacterium salinarum (earlier halobium) was solubilised in organic medium using reversed micelles of hexadecyltrimethylammonium bromide in cyclohexane, with 1-butanol as co-surfactant. The stability of alkaline p-nitrophenylphosphate phosphatase in this system was studied at different conditions, w(0) ([H(2)O]/[surfactant]), salt concentration, with and without Mn(+2). At all the conditions assayed, alkaline p-nitrophenylphosphate phosphatase was more stable in reversed micelles than in bulk aqueous solution (at 25 degrees C). The stabilisation effect of the reversed micelles was dramatic when the enzyme was dialysed against Mn(+2)-free buffer since the enzyme lost all the activity within 90 min in aqueous medium, but it retained approximately 72% of the initial enzymatic activity for 90 min in reversed micelles.
authors.affiliation: División de Bioquímica, Facultad de Ciencias, Universidad de Alicante, Aptdo. 99, 03080 Alicante, Spain. frutos@ua.es
authors.forename: F C
authors.initials: FC
authors.lastname: Marhuenda-Egea
authors.forename: S
authors.initials: S
authors.lastname: Piera-Velázquez
authors.forename: C
authors.initials: C
authors.lastname: Cadenas
authors.forename: E
authors.initials: E
authors.lastname: Cadenas
mesh_terms: D020001:1-Butanol / Q000737:chemistry; D000469:Alkaline Phosphatase / Q000737:chemistry* / Q000378:metabolism*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D003510:Cyclohexanes / Q000737:chemistry; D004795:Enzyme Stability; D019617:Halobacterium salinarum / Q000201:enzymology*; D008345:Manganese / Q000737:chemistry; D008823:Micelles; D012492:Salts; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D002593:Cetrimonium Compounds; D003510:Cyclohexanes; D008823:Micelles; D012492:Salts; D013501:Surface-Active Agents; D008345:Manganese; D020001:1-Butanol; D000469:Alkaline Phosphatase; D000077286:Cetrimonium