Isolation of rat liver plasma membranes by zonal centrifugation: increased yield with Ca2+

Rat liver plasma membranes were isolated by zonal centrifugation after homogenization of the livers in a Ca²⁺ containing medium. The yield was 37.5%, based on the recovery of 5′-nucleotidase. The membrane purity as judged enzymatically and by electron microscopy was superior to that reported for other procedures.