Phosphatidylserine biosynthesis in cultured Chinese hamster ovary cells. II. Isolation and characterization of phosphatidylserine auxotrophs
Chinese hamster ovary (CHO) cell mutants that required exogenously added phosphatidylserine for cell growth were isolated by using the replica technique with polyester cloth, and three such mutants were characterized. Labeling experiments on intact cells with /sup 32/Pi and L-(U-/sup 14/C)serine revealed that a phosphatidylserine auxotroph, designated as PSA-3, was strikingly defective in phosphatidylserine biosynthesis. When cells were grown for 2 days without phosphatidylserine, the phosphatidylserine content of PSA-3 was about one-third of that of the parent. In extracts of the mutant, the enzymatic activity of the base-exchange reaction of phospholipids with serine producing phosphatidylserine was reduced to 33% of that in the parent; in addition, the activities of base-exchange reactions of phospholipids with choline and ethanolamine in the mutant were also reduced to 1 and 45% of those in the parent, respectively. Furthermore, it was demonstrated that the serine-exchange activity in the parent was inhibited approximately 60% when choline was added to the reaction mixture whereas that in the mutant was not significantly affected. From the results presented here, we conclude the following. There are at least two kinds of serine-exchange enzymes in CHO cells; one (serine-exchange enzyme I) can catalyze the base-exchange reactions of phospholipids with serine, choline, and ethanolamine while the other (serine-exchange enzyme II) does not use the choline as a substrate. Serine-exchange enzyme I, in which mutant PSA-3 is defective, plays a major role in phosphatidylserine biosynthesis in CHO cells. Serine-exchange enzyme I is essential for the growth of CHO cells.
- Research Organization:
- National Institute of Health, Tokyo, Japan
- OSTI ID:
- 5491667
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 13
- Country of Publication:
- United States
- Language:
- English
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Isolation and characterization of a Chinese hamster ovary cell mutant with altered regulation of phosphatidylserine biosynthesis
Phosphatidylserine biosynthesis in cultured Chinese hamster ovary cells. I. Inhibition of de novo phosphatidylserine biosynthesis by exogenous phosphatidylserine and its efficient incorporation
Related Subjects
CHO CELLS
GROWTH
SERINE
BIOSYNTHESIS
BIOCHEMICAL REACTION KINETICS
CARBON 14 COMPOUNDS
CELL CULTURES
CHOLINE
ENZYME ACTIVITY
ENZYMES
HAMSTERS
MUTANTS
PHOSPHATES
PHOSPHOLIPIDS
PHOSPHORUS 32
TRACER TECHNIQUES
ALCOHOLS
AMINES
AMINO ACIDS
AMMONIUM COMPOUNDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DRUGS
ESTERS
HYDROXY ACIDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
LIPIDS
LIPOTROPIC FACTORS
MAMMALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
QUATERNARY COMPOUNDS
RADIOISOTOPES
REACTION KINETICS
RODENTS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques