PHOSPHORYLATION OF DIGLYCERIDES BY RAT BRAIN

1962 ◽  
Vol 40 (1) ◽  
pp. 247-259 ◽  
Author(s):  
K. P. Strickland
Keyword(s):  
Phosphatidic Acid ◽  
Rat Brain ◽  
Inorganic Phosphate ◽  
Specific Activity ◽  
Alkaline Treatment ◽  
Water Soluble ◽  
Two Dimensional ◽  
Relative Specific Activity ◽  
Hydrolysis Products ◽  
Stimulation Of

The addition of D-α,β-dimyristin was observed to stimulate by three to six times the labelling of phospholipids from radioactive inorganic phosphate (Pi32) by glycolysing homogenates and respiring mitochondria of rat brain. The increase in labelling was confined to the glycerophosphate (GP) isolated by two-dimensional chromatography from the water-soluble hydrolysis products obtained on weak alkaline treatment of the labelled phospholipids. The GP formed under these conditions is presumed to be derived mainly from phosphatidic acid formed by the phosphorylation of the diglyceride. A similar effect was observed for D-α,β-dipalmitin, D-α,β-diolein, and natural diglycerides prepared from either egg lecithin or spinal cord lecithin, but not for D-α-β-distearin. L-α,β-Diolein was much less effective than the D-isomer, suggesting a stereospecificity on the part of the enzymic phosphorylation of diglyceride. Experiments on the effects of the omission of Mg++ and the addition of glycolytic inhibitors on the stimulation of the labelling from Pi32 caused by D-α,β-dimyristin and D-α,β-diolein in the anaerobic homogenate system suggested that the increased phosphorylation caused by added diglycerides was closely coupled to active glycolysis. A comparison of the relative specific activity of the lipid P, following incubation of Pi32 and ATP32 in the anaerobic homogenate system inhibited by fluoride with and without D-α,β-diolein added, showed that the phosphate of the newly formed phosphatidic acid was derived from ATP, suggesting the presence of a D-α,β-diglyceride kinase.

PHOSPHORYLATION OF DIGLYCERIDES BY RAT BRAIN

1962 ◽  
Vol 40 (2) ◽  
pp. 247-259 ◽  
Author(s):  
K. P. Strickland
Keyword(s):  
Phosphatidic Acid ◽  
Rat Brain ◽  
Inorganic Phosphate ◽  
Specific Activity ◽  
Alkaline Treatment ◽  
Water Soluble ◽  
Two Dimensional ◽  
Relative Specific Activity ◽  
Hydrolysis Products ◽  
Stimulation Of

The addition of D-α,β-dimyristin was observed to stimulate by three to six times the labelling of phospholipids from radioactive inorganic phosphate (Pi32) by glycolysing homogenates and respiring mitochondria of rat brain. The increase in labelling was confined to the glycerophosphate (GP) isolated by two-dimensional chromatography from the water-soluble hydrolysis products obtained on weak alkaline treatment of the labelled phospholipids. The GP formed under these conditions is presumed to be derived mainly from phosphatidic acid formed by the phosphorylation of the diglyceride. A similar effect was observed for D-α,β-dipalmitin, D-α,β-diolein, and natural diglycerides prepared from either egg lecithin or spinal cord lecithin, but not for D-α-β-distearin. L-α,β-Diolein was much less effective than the D-isomer, suggesting a stereospecificity on the part of the enzymic phosphorylation of diglyceride. Experiments on the effects of the omission of Mg++ and the addition of glycolytic inhibitors on the stimulation of the labelling from Pi32 caused by D-α,β-dimyristin and D-α,β-diolein in the anaerobic homogenate system suggested that the increased phosphorylation caused by added diglycerides was closely coupled to active glycolysis. A comparison of the relative specific activity of the lipid P, following incubation of Pi32 and ATP32 in the anaerobic homogenate system inhibited by fluoride with and without D-α,β-diolein added, showed that the phosphate of the newly formed phosphatidic acid was derived from ATP, suggesting the presence of a D-α,β-diglyceride kinase.

HYDROLYSIS OF LECITHIN BY PLANT PLASTID ENZYMES

1955 ◽  
Vol 33 (1) ◽  
pp. 575-589 ◽  
Author(s):  
Morris Kates
Keyword(s):  
Phosphatidic Acid ◽  
Inorganic Phosphate ◽  
Organic Phosphate ◽  
Water Soluble ◽  
Lag Phase ◽  
Carrot Root ◽  
First Order ◽  
Spinach Chloroplasts ◽  
Egg Lecithin ◽  
Hydrolysis Of

Enzymatic liberation of choline from egg lecithin by plastid fractions from sugar beet, spinach, and cabbage leaves and from carrot root was a rapid, first order reaction (up to 70% hydrolysis), and was not preceded by a lag phase. None of the choline-containing products of lecithin degradation (lysolecithin, glycerylphosphorylcholine, or phosphorylcholine) lost choline on incubation with spinach chloroplasts. Inorganic phosphate liberation from lecithin by the plastids was preceded by a lag phase and was much slower than choline liberation. Spinach chloroplasts catalyzed the liberation of inorganic phosphate from L-α-phosphatidic acid and from L-α-glycerophosphate. The water-soluble organic phosphate liberated from lecithin by spinach chloroplasts was identified chromatographically as phosphorylcholine. The ether-soluble organic phosphate produced during the hydrolysis of egg lecithin by carrot plastids was isolated and identified as L-α-phosphatidic acid. These observations suggest that the enzymatic hydrolysis of lecithin by plant plastids involves the following reactions: (1) lecithin → L-α-phosphatidic acid + choline; (2) L-α-phosphatidic acid → inorganic phosphate + diglyceride and/or (3) L-α-phosphatidic acid → glycerophosphate + fatty acids and (4) glycerophosphate → inorganic phosphate + glycerol; and (5) lecithin → phosphorylcholine + diglyceride. The L-α-structure for egg lecithin was confirmed.

PHOSPHORUS METABOLISM OF THE LIVER: EFFECT OF HYPOPHYSECTOMY, ADRENALECTOMY, AND ADMINISTRATIONOF ACTH ON THE INCORPORATION OF RADIOACTIVE PHOSPHATE INTO RNA NUCLEOTIDES

1955 ◽  
Vol 33 (1) ◽  
pp. 54-61 ◽  
Author(s):  
J. E. Logan ◽  
F. C. Heagy ◽  
R. J. Rossiter
Keyword(s):  
Adrenal Cortex ◽  
Intraperitoneal Injection ◽  
Inorganic Phosphate ◽  
Adrenal Glands ◽  
Specific Activity ◽  
Phosphorus Metabolism ◽  
Relative Specific Activity ◽  
Hypophysectomized Rats

The specific activity of the liver RNA nucleotide phosphorus, relative to the specific activity of the liver inorganic phosphate, was determined in the rat, 16 hr. after an intraperitoneal injection of radioactive inorganic phosphate. The nucleotides were isolated by ionophoresis on paper strips.Hypophysectomy caused a decrease in the relative specific activity of each of the four RNA nucleotides. The administration of ACTH caused an increase in the incorporation of P32 into each of the RNA nucleotides of the liver of hypophysectomized animals, but it caused a small and statistically significant decrease in normal animals. Adrenalectomy, either in normal or in hypophysectomized rats, did not affect the P32 incorporation, nor did the administration of ACTH in the absence of the adrenal glands.It is concluded that ACTH can affect the incorporation of P32 into the RNA of the liver and that this effect is due to the action of the hormone on the adrenal cortex. However, other factors also must be operative, since removal of the adrenal glands does not cause the decrease in the P32 incorporation observed after removal of the pituitary.

PHOSPHORUS METABOLISM OF THE LIVER: EFFECT OF HYPOPHYSECTOMY, ADRENALECTOMY, AND ADMINISTRATIONOF ACTH ON THE INCORPORATION OF RADIOACTIVE PHOSPHATE INTO RNA NUCLEOTIDES

1955 ◽  
Vol 33 (1) ◽  
pp. 54-61
Author(s):  
J. E. Logan ◽  
F. C. Heagy ◽  
R. J. Rossiter
Keyword(s):  
Adrenal Cortex ◽  
Intraperitoneal Injection ◽  
Inorganic Phosphate ◽  
Adrenal Glands ◽  
Specific Activity ◽  
Phosphorus Metabolism ◽  
Relative Specific Activity ◽  
Hypophysectomized Rats

The specific activity of the liver RNA nucleotide phosphorus, relative to the specific activity of the liver inorganic phosphate, was determined in the rat, 16 hr. after an intraperitoneal injection of radioactive inorganic phosphate. The nucleotides were isolated by ionophoresis on paper strips.Hypophysectomy caused a decrease in the relative specific activity of each of the four RNA nucleotides. The administration of ACTH caused an increase in the incorporation of P32 into each of the RNA nucleotides of the liver of hypophysectomized animals, but it caused a small and statistically significant decrease in normal animals. Adrenalectomy, either in normal or in hypophysectomized rats, did not affect the P32 incorporation, nor did the administration of ACTH in the absence of the adrenal glands.It is concluded that ACTH can affect the incorporation of P32 into the RNA of the liver and that this effect is due to the action of the hormone on the adrenal cortex. However, other factors also must be operative, since removal of the adrenal glands does not cause the decrease in the P32 incorporation observed after removal of the pituitary.

scholarly journals Phospholipid association with the bovine cardiac mitochondrial adenosine triphosphatase

1985 ◽  
Vol 225 (3) ◽  
pp. 597-608 ◽  
Author(s):  
R E Brown ◽  
R I Montgomery ◽  
P I Spach ◽  
C C Cunningham
Keyword(s):  
Phosphatidic Acid ◽  
Adenosine Triphosphatase ◽  
Specific Activity ◽  
Sodium Cholate ◽  
Mitochondrial Atpase ◽  
Cardiac Mitochondria ◽  
Submitochondrial Particles ◽  
Relative Enrichment ◽  
Fold Stimulation ◽  
Stimulation Of

The association of different phospholipids with a lipid-depleted oligomycin-sensitive ATPase from bovine cardiac mitochondria [Serrano, Kanner & Racker (1976) J. Biol. Chem. 251, 2453-2461] has been examined using three approaches. First, reconstitution of the ATPase with different synthetic diacyl phospholipids resulted in a 2-10-fold stimulation of ATPase specific activity depending upon the particular phospholipid employed. The phospholipid headgroup region displayed the following order of ATPase reactivation potential: dioleoylphosphatidylglycerol greater than dioleoylphosphatidic acid greater than dioleoylphosphatidylcholine. Furthermore, the ATPase showed higher levels of specific activity when reconstituted with dioleoyl phospholipid derivatives compared with dimyristoyl derivatives. Second, examination of the phospholipid remaining associated with the lipid-depleted ATPase upon purification showed that phosphatidylcholine, phosphatidylethanolamine, and diphosphatidylglycerol were present. No relative enrichment of any of these phospholipids (compared with their distribution in submitochondrial particles) was noted. Therefore, no preferential association between the ATPase and any one phospholipid could be found in the mitochondrial ATPase. Third, the sodium cholate-mediated phospholipid exchange procedure was employed for studying the phospholipid requirements of the ATPase. Replacement of about 50% of the mitochondrial phospholipid remaining with the lipid-depleted ATPase could be achieved utilizing either synthetic phosphatidic acid or phosphatidylcholine. Examination of the displaced mitochondrial phospholipid showed that phosphatidylcholine, phosphatidylethanolamine, and diphosphatidylglycerol were replaced with equal facility.

scholarly journals NUCLEIC ACID SYNTHESIS IN TYPES 4 AND 5 ADENOVIRUS-INFECTED HELA CELLS

1961 ◽  
Vol 113 (2) ◽  
pp. 283-299 ◽  
Author(s):  
Harold S. Ginsberg ◽  
Mary K. Dixon
Keyword(s):  
Viral Infection ◽  
Hela Cells ◽  
Inorganic Phosphate ◽  
Specific Activity ◽  
Fold Increase ◽  
Sodium Formate ◽  
Acid Synthesis ◽  
Water Soluble ◽  
Viral Propagation ◽  
Infected Cells

Type 4 adenovirus infection of HeLa cells effected a marked increase in synthesis of the saline-soluble DNA fraction, but not the host-cell DNA (the water-soluble fraction). This was demonstrated by the marked increase in specific activity of saline-soluble DNA but not water-soluble DNA when P32-inorganic phosphate or sodium formate-C14 was employed. When these isotopes were used to label cells before viral infection rather than during the process of viral propagation, the saline-soluble DNA from infected cells had a specific activity of 10 to 20 per cent less than that of uninfected cells, indicating that the saline-soluble DNA was synthesized both from prelabeled precursors of the cell pools and unlabeled materials from the medium. Saline-soluble DNA began to increase between 10 to 12 hours after viral infection and 3 to 4 hours before appearance of newly propagated infectious virus. The specific activity of the acid-soluble pool of infected cells also increased between 10 to 12 hours after viral inoculation when sodium formate-C14 was used as a radioisotope. When P32-inorganic phosphate was utilized, the specific activity of infected-cell RNA was increased approximately the same relative amount as when total RNA was determined chemically; i.e., 30 to 40 per cent. With type 5 adenovirus, not only did a 3- to 5-fold increase in saline-soluble DNA occur, but also an increase was measured in specific activity of RNA when P32-inorganic phosphate was used.

PHOSPHORUS METABOLISM OF THE ADRENAL GLAND EFFECT OF HYPOPHYSECTOMY AND ADMINISTRATION OF ACTH ON INCORPORATION OF P32 INTO INORGANIC PHOSPHATE

1954 ◽  
Vol 32 (3) ◽  
pp. 251-260 ◽  
Author(s):  
B. E. Riedel ◽  
J. E. Logan ◽  
H. A. DeLuca ◽  
R. J. Rossiter
Keyword(s):  
Adrenal Gland ◽  
Intraperitoneal Injection ◽  
Inorganic Phosphate ◽  
Specific Activity ◽  
Time Intervals ◽  
Inorganic P ◽  
Relative Specific Activity ◽  
Single Intraperitoneal Injection ◽  
Hypophysectomized Rats ◽  
Significant Change

In confirmation of the work of others, the concentration of inorganic phosphate (P) in the plasma of hypophysectomized rats was found to be less than that in the plasma of control animals. Hypophysectomy caused no significant change in the concentration of inorganic P in the adrenal gland or liver. A single intraperitoneal injection of each of two preparations of ACTH failed to cause any significant change in the concentrations of inorganic P in plasma, adrenal, or liver.The specific activity of the inorganic P in the plasma of hypophysectomized rats after an intraperitoneal injection of inorganic P labelled with P32 was greater than that in the control animals. Hypophysectomy caused a decrease in the specific activity of the inorganic P of the adrenal gland relative to that of the inorganic P of the plasma. Each of the two preparations of ACTH, given to the hypophysectomized animals as a single intraperitoneal injection 20 hr. before killing, restored the relative specific activity of the inorganic P of the adrenals to normal values. When the ACTH was administered six hours before killing, one of the preparations (ACTH A) caused an increase in the relative specific activity of the inorganic P of the adrenals, but a second preparation (ACTH C) was without significant effect.The increase in the specific activity of the inorganic P of the plasma comes on slowly (quite small two days after hypophysectomy), whereas the decrease in the relative specific activity of the inorganic P of the adrenal gland comes on rapidly (maximal two days after hypophysectomy). For this reason, at longer time intervals after hypophysectomy (greater than six days) the absolute activity of the acid-soluble P of the adrenal, i.e. the activity not referred to that of the inorganic P of the plasma, was greater in hypophysectomized animals, and not less, as reported by other workers. The activity of this fraction is less in hypophysectomized animals only if the observations are made at short time intervals after removal of the pituitary. Evidence is presented for the view that the increase in the specific activity of the inorganic P of the plasma is the result of changes brought about by a deficiency of growth hormone, whereas the decrease in the relative specific activity of the adrenal is due to a deficiency of ACTH.

HYDROLYSIS OF LECITHIN BY PLANT PLASTID ENZYMES

1955 ◽  
Vol 33 (4) ◽  
pp. 575-589 ◽  
Author(s):  
Morris Kates
Keyword(s):  
Phosphatidic Acid ◽  
Inorganic Phosphate ◽  
Organic Phosphate ◽  
Water Soluble ◽  
Lag Phase ◽  
Carrot Root ◽  
First Order ◽  
Spinach Chloroplasts ◽  
Egg Lecithin ◽  
Hydrolysis Of

Enzymatic liberation of choline from egg lecithin by plastid fractions from sugar beet, spinach, and cabbage leaves and from carrot root was a rapid, first order reaction (up to 70% hydrolysis), and was not preceded by a lag phase. None of the choline-containing products of lecithin degradation (lysolecithin, glycerylphosphorylcholine, or phosphorylcholine) lost choline on incubation with spinach chloroplasts. Inorganic phosphate liberation from lecithin by the plastids was preceded by a lag phase and was much slower than choline liberation. Spinach chloroplasts catalyzed the liberation of inorganic phosphate from L-α-phosphatidic acid and from L-α-glycerophosphate. The water-soluble organic phosphate liberated from lecithin by spinach chloroplasts was identified chromatographically as phosphorylcholine. The ether-soluble organic phosphate produced during the hydrolysis of egg lecithin by carrot plastids was isolated and identified as L-α-phosphatidic acid. These observations suggest that the enzymatic hydrolysis of lecithin by plant plastids involves the following reactions: (1) lecithin → L-α-phosphatidic acid + choline; (2) L-α-phosphatidic acid → inorganic phosphate + diglyceride and/or (3) L-α-phosphatidic acid → glycerophosphate + fatty acids and (4) glycerophosphate → inorganic phosphate + glycerol; and (5) lecithin → phosphorylcholine + diglyceride. The L-α-structure for egg lecithin was confirmed.

PHOSPHORUS METABOLISM OF THE ADRENAL GLAND EFFECT OF HYPOPHYSECTOMY AND ADMINISTRATION OF ACTH ON INCORPORATION OF P32 INTO INORGANIC PHOSPHATE

1954 ◽  
Vol 32 (1) ◽  
pp. 251-260 ◽  
Author(s):  
B. E. Riedel ◽  
J. E. Logan ◽  
H. A. DeLuca ◽  
R. J. Rossiter
Keyword(s):  
Adrenal Gland ◽  
Intraperitoneal Injection ◽  
Inorganic Phosphate ◽  
Specific Activity ◽  
Time Intervals ◽  
Inorganic P ◽  
Relative Specific Activity ◽  
Single Intraperitoneal Injection ◽  
Hypophysectomized Rats ◽  
Significant Change

In confirmation of the work of others, the concentration of inorganic phosphate (P) in the plasma of hypophysectomized rats was found to be less than that in the plasma of control animals. Hypophysectomy caused no significant change in the concentration of inorganic P in the adrenal gland or liver. A single intraperitoneal injection of each of two preparations of ACTH failed to cause any significant change in the concentrations of inorganic P in plasma, adrenal, or liver.The specific activity of the inorganic P in the plasma of hypophysectomized rats after an intraperitoneal injection of inorganic P labelled with P32 was greater than that in the control animals. Hypophysectomy caused a decrease in the specific activity of the inorganic P of the adrenal gland relative to that of the inorganic P of the plasma. Each of the two preparations of ACTH, given to the hypophysectomized animals as a single intraperitoneal injection 20 hr. before killing, restored the relative specific activity of the inorganic P of the adrenals to normal values. When the ACTH was administered six hours before killing, one of the preparations (ACTH A) caused an increase in the relative specific activity of the inorganic P of the adrenals, but a second preparation (ACTH C) was without significant effect.The increase in the specific activity of the inorganic P of the plasma comes on slowly (quite small two days after hypophysectomy), whereas the decrease in the relative specific activity of the inorganic P of the adrenal gland comes on rapidly (maximal two days after hypophysectomy). For this reason, at longer time intervals after hypophysectomy (greater than six days) the absolute activity of the acid-soluble P of the adrenal, i.e. the activity not referred to that of the inorganic P of the plasma, was greater in hypophysectomized animals, and not less, as reported by other workers. The activity of this fraction is less in hypophysectomized animals only if the observations are made at short time intervals after removal of the pituitary. Evidence is presented for the view that the increase in the specific activity of the inorganic P of the plasma is the result of changes brought about by a deficiency of growth hormone, whereas the decrease in the relative specific activity of the adrenal is due to a deficiency of ACTH.

Aspects of circadian periodic changes in phosphorus metabolism in mice

1964 ◽  
Vol 206 (3) ◽  
pp. 589-598 ◽  
Author(s):  
Walter Nelson
Keyword(s):  
Inorganic Phosphate ◽  
Time Course ◽  
Specific Activity ◽  
Kinetic Studies ◽  
Phospholipid Metabolism ◽  
Liver Phospholipid ◽  
Circadian Periodicity ◽  
Relative Specific Activity ◽  
Similar Explanation ◽  
Periodic Changes

Kinetic studies on the P32 content of mouse brain phosphorus fractions following the intraperitoneal injection of P32-labeled orthophosphate were performed during two selected segments of the 24-hr time scale. The results of these studies suggest that the circadian periodicity in relative specific activity of brain phospholipids is probably a consequence of a variation in the extent of P32 incorporation into brain inorganic phosphate and is not indicative of a periodicity in the rate of intermediary phospholipid metabolism. Data on the postinjection time course of the specific activities of plasma inorganic phosphate, liver inorganic phosphate, and liver phospholipid suggest a similar explanation for the circadian periodic changes in relative specific activity of liver phospholipids. A circadian rhythm of inorganic phosphate concentration in mouse plasma is demonstrated. Consideration of a mathematical model suggests that the observed within-day variation in P32 distribution and the circadian periodicity of phospholipid relative specific activity in liver and brain are a consequence of this periodicity in plasma phosphate content. A significant within-day variation in total phosphorus content of liver was observed. The disturbance of mice incident to P32 injection has a marked effect on the plasma content of inorganic phosphate and corticosterone.

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