Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.34 (lipoprotein lipase)
 7,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The preparation of a stable, stock, radioactive, trioleoyl glycerol emulsion in glycerol and its application to the assay of lipoprotein lipase are described. The data presented indicate that this stock emulsion combines the convenience and reproducibility of commercially available, nonradioactive emulsions with the sensitivity of sonicated, radioactive, aqueous emulsions. Furthermore, in practice, this glycerol-based emulsion appears to be specific for the protamine-sensitive extrahepatic lipase, having little or no reactivity toward the hepatic lipase measured in postheparin plasma.
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PMID:Validation of a stable emulsion for the assay of lipoprotein lipase activity. 83 25

The rise in plasma triglyceride (TG) levels associated with estrogen administration has been thought to arise from impaired clearance because of the uniform suppression of post-heparin lipolytic activity (PHLA). Recently PHLA has been shown to consist of two activities: hepatic TG lipase and extrahepatic lipoprotein lipase (LPL). To determine whether estrogen might induce a selective decline in one of these activities, both hepatic TG lipase and extrahepatic LPL were measured in post-heparin plasma from 13 normal women before and after 2 wk of treatment with ethinyl estradiol (1 mug/kg per day). Hepatic TG lipase and extrahepatic LPL were determined by two techniques: (a) separation by heparin-Sepharose column chromatography, and (b) selective inhibition with specific antibodies to post-heparin hepatic TG lipase and milk LPL. Estrogen uniformly depressed hepatic TG lipase as measured by affinity column (-68 +/- 12%, mean +/- SD, P less than 0.001) or antibody inhibition (-63 +/- 11%, P less than 0.001). Extrahepatic LPL was not significantly changed by affinity column (-22 +/- 40%) or antibody inhibition (-3 +/- 42%). Direct measurement of adipose tissue LPL from buttock fat biopsies also showed no systematic change in the activated form of LPL measured as heparin-elutable LPL (+64 +/- 164%) or in the tissue form of LPL measured in extracts of acetone-ether powders (+21 +/- 77%). The change in hepatic TG lipase correlated with the change in PHLA (r = 0.969, P less than 0.01). However, neither the change in PHLA nor hepatic TG lipase correlated with the increase in TG during estrogen. The decrease in PHLA during estrogen thus results from a selective decline in hepatic TG lipase.
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PMID:Effect of estrogen on post-heparin lipolytic activity. Selective decline in hepatic triglyceride lipase. 84 52

The (potential) activities of the two lipases in human milk were determined in breast milk samples collected from Ethiopian and Swedish mothers. The major lipase in human milk is dependent on bile salts for activity and probably participates in intestinal digestion of milk lipids in the newborn. The level of this lipase in the milk did not change with time after parturition, but differed between the groups so that it was higher in the privileged Ethopian mothers than in the nonprivileged Ethiopian mothers, who in turn had a higher level than the Swedish mothers. The other lipase is a serum-stimulated lipase (lipoprotein lipase). The level of this lipase varied between samples from different mothers as well as between different samples from the same mother. It tended to be lower in samples obtained at 4 to 5 days after parturition (Swedish mothers) than in later samples. There were in this case no significant differences between nonprivileged and privileged Ethiopian mothers or between them and Swedish mothers.
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PMID:Breast milk composition in Ethiopian and Swedish mothers. IV. Milk lipases. 85 Oct 77

Experiments were carried out to examine whether the lung acts as a depot for circulating lipid, especially that absorbed from the intestine. When 0.5 ml of triolein was administered orally to rats, the triglyceride content of the lung increased 2-3 hr later, but its increase in the lungs 2-3 hr later was only of about 1/10 of that in the liver. In the fed state the triglyceride content of the lung was only about 1/8 of that of the liver. When [3H]palmitic acid was administered orally to mice its uptake by the lung 1 and 2 hr later was 1/25-40 of that by the liver. In the lung, it was incorporated into phospholipid more than into triglyceride, but in the liver it was predominatly incorporated into triglyceride. Most of the lipase activity in both the microsomal and soluble fractions of rat lung appeared to be due to lipoprotein lipase. Fasting did not decrease the lipoprotein lipase activity in either fraction. It was concluded that the lung is not important in removal of triglyceride from the blood, even during fat absorption from the intestine, and that the lung takes up circulating lipid for its own metabolism rather than for storage.
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PMID:Triglyceride metabolism in the lung. 85 18

The ontogenic development of lipoprotein lipase and liver triglyceride hydrolase was studied in the rat. The enzyme activity measured in extrahepatic tissues fulfilled the criteria of lipoprotein lipase from the onset of measurable activity, i.e. it was inhibited by protamine and 1 M NaCl and showed requirement for serum and heparin for optimal activity. In the liver, measurable amounts of triglyceride hydrolase, active at pH 8.6 were detected 6 days prior to birth. However, till the fourth postnatal day about 50% of this activity was inhibited by NaCl and its sensitivity towards protamine was also higher than that of the enzyme in adult liver. Three patterns of development of enzymic activity were observed in extrahepatic tissues. In the lung, the lipoprotein activity reached the adult values one day prior to birth, while in the kidney only 30% of adult activity were found at birth. A linear increase of enzyme activity was observed in the heart; only 25% of adult activity were detected at birth and 100% were reached only 20 days after birth. The increase in lipoprotein lipase activity in the heart was accompanied by morphological differentiation of cardiocytes and by a progressive development of the capillary bed, which might be related to the pattern of development of enzyme activity in this organ. Adipose tissue lipoprotein lipase activity in inguinal fat fell from values 15 times than adult values between the 4th and 40th postnatal days. The enzyme activity in epididymal fat increased steeply between day 10 and 40, at which time it exceeded the adult values very considerably. These findings indicate that the regulation of the development of lipoprotein lipase activity in extrahepatic tissues is governed by local factors, which can differ even in the same type of tissue, as exemplified by the difference between inguinal and epididymal fat.
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PMID:Pre- and post-natal development of lipoprotein lipase and hepatic triglyceride hydrolase activity in rat tissues. 85 10

The activity of post-heparin lipases in patients with alcoholic hepatitis and viral hepatitis was evaluated. Lipoprotein lipase and hepatic triglyceride lipase were differentiated by assay under high and low salt conditions and also by separation on heparin-agarose affinity chromatography columns. The mean activity of hepatic triglyceride lipase in the sera of liver disease patients was only 21-24% of the mean of controls, but lipoprotein lipase in patients' sera was not different from normal levels. Hepatic triglyceride lipase deficiency may partially account for the accumulation of a triglyceride-rich low density lipoprotein in liver disease.
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PMID:Hepatic triglyceride lipase deficiency in liver disease. 86 46

Two triacylglycerol lipase activities were characterized after partial purification from pig post-heparin plasma. These two lipase activities were eluted sequentially with a NaCl gradient from columns containing Sepharose with covalently linked heparin. The first lipase activity, which was eluted at 0.75M-NaCl, was not inhibited at 28 degrees C in the presence of 1M-NaCl and was not further activated by plasma apolipoproteins. The absence of this lipase activity from post-heparin plasma from hepatectomized pigs indicates that the liver plays a role in the synthesis of this enzyme. A second lipase activity, which was eluted at 1.2M-NaCl, was inhibited when assayed in the presence of 1.0M-NaCl and was activated 14-fold by an apolipoprotein isolated from human very-low-density lipoprotein. The characteristics are identical with those of lipoprotein lipase purified from pig adipose tissue.
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PMID:Characterization of two triacylglycerol lipase activities in pig post-heparin plasma. 86 28

Effects of diets containing mixtures of safflower oil, hydrogenated coconut oil with elaidate of linolelaidate on growth, fatty acid composition, serum lecithin: cholesterol acyl transferase (LCAT) and postheparin plasma lipoprotein lipase activities in essential fatty acid (EFA) deficient rats were determined. Addition of trans fatty acids to the diet lowered the growth response to linoleic acid. Both elaidate and linolelaidate accumulated in the serum and liver, imparied the conversion of oleic acid to eicosatrienoic acid and linoleic acid to arachidonic acid, and the incorporation of eicosatrienoic acid into cholesteryl esters. Trans fatty acids also influenced the fatty acid composition of testicular lipids, but much lower amounts of these acids accumlated in tests than in liver or serum. Serum lecithin:cholesterol acyl transferase activity was elevated by an EFA deficiency, was unaffected by dietary elaidate, but was significantly decreased by linolelaidate. These effects were nullified by the addition of safflower oil to the diet. Postheparin plasma extrahepatic and hepatic lipase activities were also affected by an EFA deficiency, and by the addition of elaidate or linolelaidate alone or in combination with safflower oil to the diets of EFA deficient rats. It is suggested that trans fatty acids exhibit particular effects on the metabolism of lipids in addition to aggravation of an EFA deficiency.
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PMID:Studies of effects of trans fatty acids in the diet on lipid metabolism in essential fatty acid deficient rats. 87 68

A method was developed to separate and quantitatively determine two different triglyceride lipase activities in human postheparin plasma: hepatic triglyceride lipase (H-TGL) and lipoprotein lipase (LPL). Affinity chromatography on heparin-Sepharose columns was used for the separation. Rechromatography of purified H-TGL on heparin-Sepharose resulted in recoveries of 74 and 97% of these enzyme activities, respectively. The analytical errors for the determinations of the two activities were 11.4 and 9.6%, respectively.
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PMID:Quantitative determination of hepatic and lipoprotein lipase activities from human postheparin plasma. 89 46

The present study describes a simple method for the purification of bovine milk lipoprotein lipase based on affinity chromatography on agarose containing covalently linked heparin and the use of a non-ionic detergent, Triton X-100. By this procedure miligram amounts of detergent-free lipoprotein-ionic lipase with a specific activity of 28.9 mmoles free fatty acid/mg protein/mg protein/hour can be obtained. The apparent molecular weight of the polypeptide as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate is 55,000. The purified triacylglycerol lipase also hydrolyzes monoacylglycerol, but the activity against this lipid is 40 times lower than that against triacylglycerol.
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PMID:Purification of bovine milk lipoprotein lipase with the aid of detergent. 89 17


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