SEPARATION OF MICROSOMAL CYTOCHROME B(5) VIA PHASE-SEPARATION IN A MIXED-SOLUTION OF TRITON X-114 AND CHARGED DEXTRAN

The successful introduction of a charged dextran into the Triton X-114 phase separation system for the selective extraction of cytochrome b( 5) (cyt. b(5)) in liver microsomes is described. In the absence of cha rged dextran, 55% of total microsomal proteins and 84% of cyt. b(5) we re extracted into the surfactant-rich phase. In the presence of anioni c dextran sulfate, the extractability of total microsomal proteins was greatly reduced while that of cyt. b(5) was increased. After triplica te extraction, cyt. b(5) was purified more than 10-fold from microsome s with a recovery of 91% in the surfactant-rich phase. In view of its operational simplicity, this method provides a good means for the part ial purification of cyt. b(5) prior to chromatographic separations. (C ) 1998 Elsevier Science B.V.