Phosphatidylglycerol synthesis in castor bean endosperm. [Ricinus communis]

Journal Article · Tue Jan 01 04:00:00 EST 1974 · Plant Physiol.; (United States)

OSTI ID:7295899

Moore, Jr, T S

The synthesis of phosphatidylglycerol in castor bean (Ricinus communis var. Hale) endosperm tissue was found to be located in both the endoplasmic reticulum and mitochondrial fractions separated on sucrose density gradients. The enzyme of both fractions attained maximum activity at 5 mM Mn/sup 2 +/, 0.075 percent Triton X-100, and pH 7.3. The addition of dithiothreitol produced little effect, but sulfhydryl inhibitors reduced activity in both systems. Cytidine diphosphate-diglyceride exhibited an apparent Michaelis constant for the endoplasmic reticulum enzyme of 2.8 ..mu..M and for the mitochondrial enzyme of 2.0 ..mu..M; the maximum reaction rate was achieved at about 20 ..mu..M. For the second substrate, glycerol-phosphate, the apparent Michaelis constant for both fractions was about 50 ..mu..M and maximum velocity was reached at 400 ..mu..M. The specific activity of the mitochondrial enzyme was generally twice that of the endoplasmic reticulum.

• Research Organization: Univ. of California, Santa Cruz
• OSTI ID: 7295899
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 54; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550300 -- Cytology
59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
BIOCHEMISTRY
BIOMASS
BIOSYNTHESIS
CASTOR
CELL CONSTITUENTS
CHEMISTRY
ENDOPLASMIC RETICULUM
ENDOSPERM
ENERGY SOURCES
ENZYMES
ESTERS
GLYCEROL
HYDROXY COMPOUNDS
LIPIDS
MEDICINAL PLANTS
METABOLISM
MITOCHONDRIA
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
PHOSPHOLIPIDS
PLANT TISSUES
PLANTS
RENEWABLE ENERGY SOURCES
SYNTHESIS