Plasma Membranes of Rat Liver: Isolation of Lipoprotein Macromolecules

Abstract

Three high-denisity lipoprotein classes and one protein were separated from rat-liver plasma in membranes that had been treated with mild sonic oscillation. The lipoproteinis were separated and identified by techniques in which ultracentrifugation was used. Enzyme markers and electron-microscopic examination revealed membrane preparations essentially free of contaminating cellular partictulates.

Plasma Membranes of Mammalian Cells

“…These three features--junctional complexes, large pieces of membrane, and microvilli--provide excellent morphological criteria for the identification of liver plasma membranes in homogenates and subcellular fractions. They have been utilized in virtually all isolations of plasma membranes from liver (see especially Neville, 1960;Emmelot et al, 1964;Coleman and Finean, 1966;Barclay et al, 1967;Benedetti and Emmelot, 1968;Fleischer and Fleischer, 1969;. These morphological features are undoubtedly one source of the liver's popularity as a starting material in plasma membrane studies.…”

“…1970;Giacobino and Perrelet, 1971 ;Wolff and Jones, 1971), ATPase(s) (Wallach andKamat, 1964, 1966;Barclay et al, 1967;Bosmann et al, 1968;Evans, 1969;Fleischer and Fleischer, 1969;Molnar et al, 1969;Evans, 1970;Gahmberg and Simons, 1970;Lutz and Frimmer, 1970;Ray, 1970;Yamashita and Field, 1970;Giacobino and Perrelet, 1971;Wolff and Jones, 1971), alkaline phosphatase (HUbscher et al, 1965;Porteous and Clark, 1965;Bosmann et al, 1968;Forstner et al, 1968;Graham et al, 1968;Ray, 1970;Wilfong and Neville, 1970), leucine aminopeptidase (Htlbscher et al, 1965;Porteous and Clark, 1965;Dod and Gray, 1968;Forstner et al, 1968;Graham et al, 1968;Evans, 1969Evans, , 1970, adenyl cyclase (McKeel and Jarett, 1970;Ray, 1970;Yamashita and Field, 1970;Pohl et al, 1971;Wolff and Jones, 1971), and/or morphological criteria as markers.…”

“…Some investigators have circumvented the problem in this case by using two or more mitochondrial markers--for instance, cytochrome c oxidase for the inner and monoaminoxidase for the outer membranes (Barclay et al, 1967;Erecinska et al, 1969). A better solution to all of these difficulties introduced by the fragmentation of organelles would be to avoid such fragmentation.…”

“…Isopycnic density gradient centrifugation has proven rather successful in isolating plasma membrane fragments from the other components of tissue homogenates (e.g., Emmelot et al, 1964;Eichholz and Crane, 1965;Ei-Aaser et al, 1966;Barclay et al, 1967;Neville, 1967;Stein et al, 1968;Boone et al, 1969;Molnar et al, 1969;Barber and Jamieson, 1970;McKeel and Jarett, 1970). In the case of rat liver the plasma membrane fragments bands at a buoyant density of 1.16-1.19 (e.g., Weaver and Boyle, 1969;Ray, 1970).…”

“…Despite the dangers, ice-cold water containing 1 mM NaHCO8 has been used as the homogenization medium in preparing plasma membranes from the liver of rats (Neville, 1960;Davidson et al, 1963;Tria and Barnabei, 1963;Skipski et al, 1965;Ashworth and Green, 1966;Finean, 1966, 1967;Emmelot and Bos, 1962Finean et al, 1966;Higgins and Green, 1966;Barclay et al, 1967;Lansing et al, 1967;Lieberman et al, 1967;Song and Bodansky, 1967;Dod and Gray, 1968;Graham et al, 1968;Erecinska et al, 1969;Evans, 1969;Wattiaux-de Coninck and Wattiaux, 1969;Evans, 1970;Skidmore and Trams, 1970;Ray, 1970;Barancik and Lieberman, 1971;Franklin and Trams, 1971), Finean, 1966, 1967), (Evans, 1970), (Lutz and Frimmer, 1970), guinea pigs mice pigs the kidneys of rats guinea pigs bovine thyroid bovine mammary gland rat brown and white adipose tissue (Davidson et al, 1963), Finean, 1966, 1967), (Yamashita and Field, 1970), (Keenan et al, 1970), (Giacobino and Perrelet, 1971). Strongly hypotonic conditions with Tris replacing the bicarbonate have been used in the homogenization of HeLa Cells (Atkinson and Summers, 1971).…”