On the use of free-flow electrophoresis in subfractionation of smooth muscle microsomes

The primary objective of this work was to determine whether the heterogenous microsomal fraction prepared from rat stomach muscle by conventional differential centrifugation can be further fractionated into more purified subfractions by free-flow electrophoresis based upon differences in their net surface changes. It was found that plasma membranes showed the greatest electrophoretic mobility and can be separated effectively from the endoplasmic reticulum and mitochondrial fractions. However, the usefulness of the free-flow electrophoresis technique was compromised by substantially reduced total recovery of plasma membrane and endoplasmic reticulum marker enzyme activities. This suggests that some membrane-bound enzymes may be partially inactivated by the high electric field applied across the membrane separation chamber.