Abstract
This paper reports the results of investigations of the reaction behavior and the higher order structure of Rhizopus delemar lipase solubilized in a bis(2-ethylhexyl) sulfosuccinate sodium (AOT) reverse micellar system. In the triolein hydrolysis by lipase, the initial reaction rate depended on the organic solvent used to prepare the micellar phase. The highest rate was obtained in the system prepared with isooctane. In the isooctane system, the initial reaction rate strongly depended on the water content W0 (= [H2O]/[AOT]) and was maximal when W0 = 13. From circular dichroic (CD) measurement, far-UV CD spectra of lipase depended on the organic solvent species, and the lowest ellipticity value was obtained in the isooctane system. The ellipticity values at 222 nm in the isooctane system were changed with the W0 value, increased steeply above W0 > 13. These results suggest that in the reverse micellar system, the higher order structure of lipase is related to whether the lipase in the system fully expresses its activity.
