Regulation of the catalytic activity and oligomeric composition of enzymes in reversed micelles of surfactants in organic solvents

• Published in: FEBS letters 1991-01, Vol.278 (2), p.143-146
• Main Authors: Kabanov, Alexander V., Nametkin, Sergey N., Klyachko, Nataliya L., Levashov, Andrey V.
• Format: Article
• Language: English
• Subjects: Aerosol OT; Aerosole OT (sodium bis(2-ethylhexyl)sulfosuccinate); Alkaline phosphatase; Alkaline Phosphatase - chemistry; Alkaline Phosphatase - metabolism; alpha -chymotrypsin; Analytical, structural and metabolic biochemistry; Animals; AOT; Biological and medical sciences; Catalysis; Cattle; CBZTNP; Chymotrypsin - chemistry; Chymotrypsin - metabolism; enzyme models; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; General aspects, investigation methods; Hydrogen-Ion Concentration; Intestinal Mucosa - enzymology; Macromolecular Substances; Micellar enzymology; Micelles; Molecular Structure; N-benzloxycarbonyl-L-tyrosine p-nitrophenylphosphate; Octanes; Pancreas - enzymology; Reversed micelle; SPDP; succimidyl-3-(2-pyridylthio)propionate; Water; α-Chymotrypsin
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(91)80103-A

The Phenomenon of the regulation of the catalytic activity of enzymes via changing their oligomeric composition in the system of reversed micelles of sodium bis(2-ethylhexy)sulfosuccinate (AOT) in octane was studied using z-chymotrypsin (CT) from bovine brain and alkaline phosphatase (AP) from calf intestinal mucosa. The dependences of the enzyme catalytic activity on the AOT hydration degree ( W=[H 2O][AOT]), the parameter determining the radius ( r 4) of the inner cavity of micelles, usually represent the bell-shaped curves. The maximal catalytic activity is observed at such W o when r 4 is equal to the size of the enzyme molecule. The position of this maximum strictly correlates with the enzyme oligomeric composition. Thus, in the case of CT this is observed at W o =12 when r 1 is equal to the radius ( r p ) of the CT globule. In the case of artificially produced conjugate containing six cross-linked CT molecules, this is observed at W o=43 when r 4 is equal to the radius of the sphere surrounding the absolute octahedron composed of six CT globules. The dependence of the catalytic activity of AP on Wo represent a curve with two maxima that are observed when r 4 is equal to r p of either AP monomer ( W=17) or AP dimer ( W o=25), Ultracentrifugation experiments revealed that variation of W o causes a change in the oligomeric composition of AP its transition from monomeric ( W o 20). Hence, the observed maxima correspond to functioning of different oligomeric forms of AP.