Introduction: Crude vegetable oils contain some quantities of Phospholipids. The highest concentration of phospholipids is usually found in crude soybean oil. The presences of phospholipids in the crude and refined oils create undesirable effects on the quality and quantity of the oil during refining operations or use by the consumer. However, if phospholipids are extracted properly from the oil they could have valuable applications in many food systems. There are limited numbers of oil plants that extract soya lecithin in Iran and separate phospholipids from soyabean oil and distribute this valuable by product as soya Lecithin in the market. In this study two dimensional thin layer chromatography has been applied to measure the extracted phospholipids from five varieties of soyabeans both qualitatively and quantitatively.Materials and Methods: Five varieties of soybean cultivated in Iran (Sahar, Sims, Williams, Gorgan3 and Hill) have been studied. The isolated phospholipids for each variety was further separated into their individual constituents using two dimensional thin layer chromatography method and the concentrations were calculated on the basis of the four main phospholipids present in soybean oil that included; phosphatidyl choline, phosphatidyl ethanolamin, phosphatidyl inositol and PHOSPHATIDIC ACID.Results: The amount of total phosphatidies as percent was 1.57, 1.61, 1.72, 1.53 and 1.71% in Sahar, Hill, Williams, Gorgan and Sim varieties, respectively.Conclusion: The results showed that the highest concentration of phosphatidyl choline and phosphatidyl inositol was found in Williams’s variety and the highest amount of phosphatidyl ethanolamin and PHOSPHATIDIC ACID were found in Sahar and Sims varieties.

The mechanism by which bi-and trivalent cations affect human liver phosphatidate phosphohydrolase (PAP) activity was investigated. Bivalent cations up to 1 mM increased PAP activity whereas at higher concentrations the activity of the enzyme decreased. The stimulatory concentration for trivalent cations such as Al3+ and Cr3+, however, was much lower being 2 m M and 1 m M, respectively. All cations affecting PAP activity were also able to induce phase transition of phosphatidate from lamellar (La) to inverted hexagonal (HII) form. The rate of La-HII transition was different for each cation. At 100 mM concentration of Mg2+ only 26% of the original phosphatidate remained in La form and for other cations tested ranged from 14.5% to 76%. The phase transition was blocked by EDTA. Magnesium from 0.8 to 1.5 mM concentration raised PAP activity (3-fold) with La form of substrate but not with the HII phase. Monovalent cations such as Na+ and K+ neither affected enzyme activity nor substrate configuration. These data suggest that cation-induced PAP activation is not as a result of cation-protein interaction, but is due to formation of a suitable substrate configuration for the enzyme catalysis during phosphatidate phase transition. It appears that the real substrate configuration for PAP activity is situated between La and HII phases.

Phosphatidate phosphohydrolase (PAP2b, fraction b) was purified from the plasma membrane of rat liver cells. The Km for the surface concentration of PHOSPHATIDIC ACID was 0.43 mol%. The subunit of the enzyme had an M.W. of 33.8 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis. The native enzyme shows a molecular weight of 182 kDa in a gel filtration column packed with Sephacryl S300 in the presence of Triton X-100. The pH optima obtained for PAP2b were 5.5 and 7 in imidazole and Tris- HCl buffers, respectively. The membrane homogenate enzyme (PAP2) consumed the lamellar (La) phase of phosphatidate and was activated (approximately 3-fold) by Lubrol PX, CTAB and Tween 80 and inhibited by Zn2+ and Mn2+. The inhibition was concentration dependent. These cations affected PAP2b activity through the phase transition of phosphatidate from lamellar (La) to inverted hexagonal (HII) form. Guanidine hydrochloride and urea increased PAP2 activity (2-fold) up to 20mM concentrations by stabilizing the La phase. Optimum activity of purified PAP2b was obtained at 3% trehalose and 7% sucrose. The data suggested that the stability of the La form of phosphatidate by detergent micelles may take place through surface dilution processes.

Background: Phosphatidate phosphohydrolase enzyme (PAP) catalyzes the transformation of PHOSPHATIDIC ACID to Pi and diacylglycerol. Two different forms of PAP have been reported in rat hepatocytes: PAP1 which participates in the synthesis of phospholipids and triacylglycerols, and PAP2 which is primarily involved in lipid signaling transduction. PAP2 has two isoforms n amely PAP2a and PAP2b. In this study, the role of essential histidine residues in PAP2b was assessed.Materials and Methods: The rat liver plasma membrane was solved using N-octyle glycoside and PAP2b purified during several chromatography steps. The fixed kenitics were assessed based on superficial kenitic dilution model. Gel electrophoresis (SDS-PAGE) was discontinually performed to evaluate the purity, quantity and molecular weight measurement of enzyme subunit in gel 10%. The number of existing histidine moles in one enzyme mole (purification) was determined based on the formation of N-carbetoxy histidine.Results: Specific activity of the purified enzyme (PAP2b) was 7350 mu/mg protein. PAP2b electrophoresis showed only a single band on SDS-PAGE with a mass weight of 33.8 Kd. The PAP2b was inactivated by diethylpyrocarbonate (DEPC). The inhibition was competitive with respect to phosphatidate and there were 6 modified moles of histidine residues per mole of PAP2b.Conclusion: The data have shown that the incubation of PAP2b by DEPC plus phosphatidate can prevent the inhibitory effect of DEPC on enzyme activity. Our findings also revealed the role of histidine in the active site of PAP2b.This enzyme is likely to have the same hydrolysis catalytic mechanism as its super family through a phosphohistidine intermediate.

Objective(s): Phosphatidate phosphohydrolase (PAP) catalyzes the dephosphorylation of PHOSPHATIDIC ACID to yield Pi and diacylglycerol. Two different forms of PAP in rat hepatocyte have been reported. PAP1 is located in cytosolic and microsomal fractions and participates in the synthesis of triacylglycerols, phosphatidylcholine, and phosphatidylethanolamine, whereas the other form of phosphatidate phosphohydrolase (PAP2) is primarily involved in lipid signaling pathways. In rat liver, PAP2 has two isoforms; one PAP2a and another PAP2b. In this study, essential histidine residues were investigated in native form of rat purified PAP2b with diethylpyrocarbonate.Materials and Methods: PAP2b purified from rat liver plasma membrane by solubilizing with n-octyle glucoside and several chromatography steps. Gel electrophoresis (SDS-PAGE) performed on purified enzyme in order to evaluate its purity and to measure the molecular weight of the enzyme subunit. The enzyme inactivated with diethylpyrocarbonate (DEPC) and the number of moles of histidine residues modified per mol of enzyme determined.Results: The specific activity of purified enzyme was 7350mU/mg protein and it showed only a single band on SDSPAGE with a MW of about 33.8 kDa. The PAP2b inactivated by DEPC. The maximum 6 moles of histidine residues modified per mole of PAP2b, when about 90% of enzyme activity is lost with DEPC. Conclusion The data showed that the incubation of PAP2b by DEPC can inhibit enzyme activity. Our findings also, revealed the presence of essential histidines in the structure of PAP2b which involve in its activity. This enzyme is likely to have a similar hydrolysis catalytic mechanism as its super family through a phosphohistidine intermediate.

Different phospholipids namely, phosphatidyl ethanolamine, phosphatidyl choline and PHOSPHATIDIC ACID were used to evaluate their synergistic activities with Gallic ACID.Antioxidative activities of phospholipids were studied in tallow olein at 150 ° C at 0.01%, 0.04% and O.08% concentration, by measuring induction time. Rancimat apparatus was employed as a mean to evaluate the antioxidant activity and to determine the induction periods of the samples.The results showed that the addition of phosphatidyl ethanolamine exhibited synergistic activity with Gallic ACID while PHOSPHATIDIC ACID showed such activity only at low concentration and phosphatidyl choline was inactive.

Rosemary plant extract as a natural anti-oxidant is 4 times stronger than synthetic anti-oxidant like BHT and BHA. For this reason, it has been under attention not only for its anti-oxidant properties rather for its anti-inflammatory, anti-tumor, anti-bacterial, and anti-virus properties in different studies. This research investigates the effects of temperature, time, pH, and substance concentration in the labeling of irradiated rosmarinic ACID by radioisotope gallium-67 as a high-resolution imaging agent for SPECT imaging. In this study, gamma irradiated rosmarinic ACID nanoparticles at 20 kGy and 30 kGy levels in two concentrations of 0.5 and 1% were radiolabeled by gallium-67 radioisotope produced in Karaj cyclotron, and their efficiency and radiochemical purity were compared. Labeling conditions (including pH, temperature, time, and compound concentration) were investigated. Quality control was performed by thin-layer chromatography (RTLC). Resulting from the experiments, 30 kGy level and 1% concentration at 45 °C for 30 minutes at pH = 5.5-6 proved to be the best time for labeling rosemary nanoparticles, and the highest radiochemical purity achieved was 95%; radio conjugate also showed good stability after 12 hours.

Introduction: Phospholipids, might be regarded as preventive antioxidant and some might exhibit synergistic effects on the oil stability. It is the aim of this research work to examine the antioxidant and carry through properties of some phospholipids in fractionated sheep tail fat, the olein fraction.Materials and Methods: In this research work, antioxidant activitiy of some phosphatides namely phosphatidyl choline, phosphatidyl ethanolamine and PHOSPHATIDIC ACID (Sigma Chemical Company) were studied in mutton tallow, the olein fraction at 150°C, by induction period measurements. Rancimat apparatus was employed as a mean to evaluate the induction periods of the samples. Carry- through properties of selected phospholipids was calculated by detection of Standard Coefficient.Results: The results showed that the addition of phosphatidyl choline and phosphatidyl ethanolamine slightly increased the oxidative stability of tallow olein while PHOSPHATIDIC ACID showed no antioxidant effect.Conclusion: Antioxidant activity of phosphatidyl ethanolamine was more than phosphatidyl choline at low temperatures. Antioxidant activity of phosphatidyl ethanolamine decreased faster than phosphatidyl choline as the temperature was increased. Therefore Standard Coefficient of phosphatidyl choline is greater than phosphatidyl ethanolamine.