Lipid composition of organelles from germinating castor bean endosperm

Journal Article · Mon Jan 31 23:00:00 EST 1977 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.59.2.259· OSTI ID:5238022

Donaldson, R P; Beevers, H

Glyoxysome, endoplasmic reticulum, mitochondria, and proplastid fractions were isolated from endosperm of castor beans (Ricinus communis) germinated for 5 days at 30 C. Samples from sucrose density gradients were diluted with 0.15 M KCl and the membranes pelleted. Lipid extracts of these membranes were analyzed for phosphoglyceride, acyl lipid, and sterol content. The endoplasmic reticulum contains 1.24 ..mu..mol of phosphoglyceride per mg of protein; the mitochondria, 0.65 ..mu..mol/mg; and the glyoxysome membranes, 0.55 ..mu..mol/mg. Phosphatidyl choline and phosphatidyl ethanolamine are the most abundant lipids in all membranes studied, accounting for 70% or more of the lipid phosphorus and 50% or more of the fatty acid. Glyoxysome membranes and endoplasmic reticulum also contain phosphatidyl inositol (respectively, 9 and 17% of the lipid phosphorus) and free fatty acids (13% of the total fatty acid in each). Compared with other organelles, mitochondrial membranes have more phosphatidyl ethanolamine relative to phosphatidyl choline and are characterized by the presence of cardiolipin, in which 80% of the fatty acid is linoleate. The relative amounts of linoleate, palmitate, oleate, stearate, and linolenate in each of the phosphotoglycerides are constant regardless of the membrane source. Stimasgasterol and ..beta..-sitosterol are present in the membranes (1 to 9 nmol each/mg protein). The data provide further evidence that glyoxysome membranes are derived from the endoplasmic reticulum but at the same time indicate some differentiation.

• Research Organization: Univ. of California, Santa Cruz
• OSTI ID: 5238022
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 59:2; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
AMINES
AMMONIUM COMPOUNDS
BIOCHEMISTRY
BIOMASS
CARBOHYDRATES
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CASTOR
CELL CONSTITUENTS
CHEMICAL COMPOSITION
CHEMISTRY
CHOLINE
DISACCHARIDES
ELEMENTS
ENDOPLASMIC RETICULUM
ENDOSPERM
ENERGY SOURCES
ESTERS
ETHANOL
GERMINATION
HEXADECANOIC ACID
HYDROXY COMPOUNDS
LINOLENIC ACID
LIPIDS
LIPOTROPIC FACTORS
MEDICINAL PLANTS
MEMBRANES
MITOCHONDRIA
MONOCARBOXYLIC ACIDS
NONMETALS
OLEIC ACID
OLIGOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
PHOSPHOLIPIDS
PHOSPHORUS
PLANT TISSUES
PLANTS
QUATERNARY COMPOUNDS
RENEWABLE ENERGY SOURCES
SACCHARIDES
SACCHAROSE
STEARATES