title: Kinetics and stability of delta 5-3-ketosteroid isomerase from Pseudomonas testosteroni in the system of reverse micelles of aerosol OT in isooctane.
abstract: Partially purified delta 5-3-ketosteroid isomerase (KSI) from Pseudomonas testosteroni was studied kinetically after solubilization in reverse micelles of aerosol OT (AOT) in isooctane and water, as regards its application to biotechnology. With delta 5,10-estren-17 beta-ol-3-one as a substrate, KSI displays an enzyme activity in the micellar system but a low stability. In the presence of urea, the enzyme is, however, stable. Kinetic parameters of the stabilized enzyme are highly sensitive to both the hydration degree of the surfactant and its concentration. The hypothesis of the geometric correspondence of a non-spherical enzyme and spherical micellar matrix is considered.
authors.affiliation: Département de Biochimie, UFR Biomédicale des Saints-Pères, Paris, France.
authors.forename: A V
authors.initials: AV
authors.lastname: Levashov
authors.forename: B
authors.initials: B
authors.lastname: Khettal
authors.forename: S
authors.initials: S
authors.lastname: de Lauzon
authors.forename: M
authors.initials: M
authors.lastname: Waks
authors.forename: N
authors.initials: N
authors.lastname: Cittanova
mesh_terms: D000336:Aerosols; D002384:Catalysis; D004143:Dioctyl Sulfosuccinic Acid / Q000494:pharmacology; D004789:Enzyme Activation; D004795:Enzyme Stability / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008823:Micelles; D009795:Octanes; D011549:Pseudomonas / Q000201:enzymology*; D013251:Steroid Isomerases / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification; D014508:Urea / Q000494:pharmacology
chemical_list: D000336:Aerosols; D008823:Micelles; D009795:Octanes; D004143:Dioctyl Sulfosuccinic Acid; D014508:Urea; D013251:Steroid Isomerases; C022660:steroid delta-isomerase; C045798:2,2,4-trimethylpentane