AJP - Gastrointestinal and Liver Physiology, Vol 244, Issue 4 347-G356, Copyright © 1983 by American Physiological Society
Empirical strategy for analytical fractionation of epithelial cells
A. K. Mircheff
Despite the importance of cell fractionation methods in studies of
epithelial transport mechanisms and of a variety of subcellular processes,
current practices in cell fractionation have a number of shortcomings. Most
cell fractionation studies depend on biochemical markers, but they provide
little independent confirmation of the initial assumptions that markers are
uniquely associated with particular subcellular structures and that they
are uniformly distributed over the surfaces with which they are associated.
Moreover, it is generally difficult and time-consuming to design new
membrane isolation procedures. After reviewing the analytical nature of
physical separation procedures, I suggest an empirical approach to cell
fractionation that is both general and comprehensive. This approach uses
physical separation procedures to generate spatial distributions of
particles in which position is related to such physical properties as
sedimentation coefficient, density, cholesterol content, surface charge,
and coefficient of partitioning in aqueous polymer two-phase systems.
Determination of the frequency distributions of biochemical markers permits
detection of separate populations of particles even when the populations
lack unique markers. This process requires no a priori assumptions about
the subcellular localizations of particles.
