Analytical characterization of beet root vacuole membrane
Vacuoles from beet root (Beta vulgaris L. var. esculenta Gurke) isolated by a mechanical procedure were osmotically lysed to separate the membrane and sap components for analysis. Approximately 62% of the vacuole proteins, 70% of the nondialyzable carbohydrates and almost all of the phospholipids and sterols were recovered in the membrane fraction. The vacuole membrane had a phospholipid:protein ratio of 0.68 and a sterol:phospholipid ratio of 0.21. Seventeen complex polar lipids including phosphatides ad glycolipids have been tentatively identified. Phosphatidylcholine (54%) and phosphatidylethanolamine (24%) were the most prominant phosphoglycerides besides phosphatidylserine, phosphatidylglycerol, phosphatidylinositol, and phosphatidic acid (1, 4, 5, and 12%, respectively. A putative sulfoglycoside and two major ceramide glycoside-like lipids, resembling those of animal lysosomes, were identified by thin-layer chromatography. High-resolution SDS-acrylamide gel electrophoresis of the polypeptides from the vacuole revealed 15 major bands with apparent molecular weights ranging from 91,000 to 12,000. Selective elution experiments delineated those polypeptides that were peripheral membrane proteins or sap proteins adsorbed to the membrane, and those that exhibited hydrophobic interaction with the lipid core. Lectin labeling results indicated that most of the polypeptides from the membrane and from the sap were glycoproteins probably of the high-mannose type characteristic of lysosomal enzymes that have undergone several stages of posttranslational modification.
- Research Organization:
- Harvard Univ., Cambridge, MA (United States)
- OSTI ID:
- 5178826
- Journal Information:
- J. Cell Biol.; (United States), Vol. 87
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BEETS
CELL MEMBRANES
CHEMICAL COMPOSITION
CARBOHYDRATES
ELECTROPHORESIS
GLUCOPROTEINS
GLYCOLIPIDS
LABELLING
LECITHINS
LECTINS
PHOSPHOLIPIDS
PLANT CELLS
PROTEINS
STEROLS
THIN-LAYER CHROMATOGRAPHY
CELL CONSTITUENTS
CHROMATOGRAPHY
ESTERS
FOOD
HYDROXY COMPOUNDS
LIPIDS
MEMBRANES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
SACCHARIDES
SEPARATION PROCESSES
STEROIDS
VEGETABLES
550200* - Biochemistry