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CP: Chemische Physik
CP 30: Poster: Biologische Systeme
CP 30.4: Poster
Monday, March 22, 1999, 18:00–20:00, R52/R72
Direct Visualization of Morphological Enzyme Activity — •S. Hubert and H.-G. Döbereiner — Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Kantstrasse 55, 14513 Teltow-Seehof
We report on experiments of phospholipase attack on giant uni-lamellar
vesicles in aqueous solution. Observations are performed under a phase-contrast
microscope employing a special flow chamber which allows in situ injection of
enzyme into the external medium of the vesicles. Thus, the time course
of events can be studied directly. With the phospholipase PLA2, we find the
following sequence of events: After an initial lag phase, the vesicles loose
their optical contrast which indicates an exchange of solution across the
membrane via small pores. Then, spherical vesicles start to shrink
continuously,
presumably expelling micelles composed of reaction products into solution.
This process continues until the vesicles are no
longer visible under the microscope.