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)

A preparation of cerebral microvessels was used to demonstrate the presence of lipoprotein lipase and acid lipase activity in the microvasculature of rabbit brain. Microvessels, consisting predominantly of capillaries, small arterioles, and venules, were islated from rabbit brain. Homogenates were assayed for lipolytic activity using a glycerol-stabilized trioleoylglycerol-phospholipid emulsion as substrate. Lipoprotein lipase activity was characterized with this substrate by previously established criteria including an alkaline pH optimum, increased activity in the presence of heparin and heat-inactivated plasma, and reduced activity in the presence of NaCl and protamine sulfate. A different substrate, containing trioleoylglycerol incorporated into phospholipid vesicles, was used to reveal acid lipase activity that was not affected by heparin, plasma, NaCl, or protamine sulfate. Lipoprotein lipase did not show activity with the vesicle preparation as substrate. Intact microvessels, when incubated in the presence of heparin, release lipoprotein lipase into the incubation solution. In contrast, release of acid lipase activity from intact microvessels was not dependent on heparin. The data show the presence of both lipoprotein lipase and acid lipase in brain microvessels and suggest that lipoproteins are metabolized within the cerebral vasculature.
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PMID:Lipoprotein lipase and acid lipase activity in rabbit brain microvessels. 3 80

In 5 French Alpine goats, omental adipose tissue acetyl-CoA carboxylase, glucose-6-phosphate deshydrogenase, malic enzyme and lipoprotein lipase activities significantly decreased during the third month of gestation, whereas plasma non-esterified fatty acid and triacyglycerol contents increased. This probably reflects an early decreasing rate of adipose tissue anabolism during gestation in the Goat. At the third week of lactation, anabolic activities relative to DNA content of adipose tissue were extremely low, and the tissue weight relative to DNA was lower than during gestation. Metabolic alterations of omental adipose tissue in early lactation do not seem to be related to milk production level. These results could contribute to a better control of the kinetic of body lipid stores during the reproductive cycle in high milk yielding ruminants.
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PMID:[Metabolic activity of adipose tissue in the goat during gestation and at the beginning of lactation]. 3 15

The kinetics of thermal inactivation of cow's milk lipoprotein lipase (LPL) was studied. LPL inactivation can be described by the first order q equation. Thermodynamic parameters of LPL inactivation were calculated. In the range of physiological temperatures LPL existed as two conformers. The temperature of conformation conversion was 41.5 degrees C. Glycerol increased thermal stability of milk, whereas water dilution of milk, pH shift to the acid or alkaline zone, and glycine addition to milk decreased it. It is suggested that casein micellae stabilize milk LPL.
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PMID:[Thermal inactivation of milk lipoprotein lipase]. 4 51

A rabbit antiserum prepared against the serum-stimulated lipase (lipoprotein lipase) from bovine milk crossreacted with serum-stimulated lipases from human milk and from human postheparin plasma, but not with bile salt-stimulated lipase from human milk or with salt-resistant lipase from human postheparin plasma. Thus, the serum-stimulated lipase in bovine milk has immunological determinants in common with the serum-stimulated lipases in human milk and in human postheparin plasma. The time-courses for the appearance of serum-stimulated lipase and salt-resistant lipase activities in human plasma after heparin injection were different. The two activities were separated by heparin-Sepharose chromatography. After treatment of postheparin plasma with the antiserum only the salt-resistant lipase activity could be eluted from the column. Thus, these two enzyme activities in postheparin plasma reside in two different enzyme molecules.
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PMID:Serum-stimulated lipases (lipoprotein lipases). Immunological crossreaction between the bovine and the human enzymes. 4 50

Glycosaminoglycans (GG) were isolated from commercial Ateroid and compared with those from bovine duodenal mucosa and pancreas. The major GG in Ateroid is heparin. Heparan sulfate (HS) and dermatan sulfate were also found. HS, chondroitin sulfates, and heparin were isolated from duodenal mucosa after papain digestion, but a residue, non-digestible, was mostly heparin. Pancreas contains very little GG, and the GG composition is similar to that of mucosa. The heparin isolated from Ateroid and mucosa have similar lipoprotein lipase-releasing activity, but the former has considerably less anticoagulant activity. Interestingly, papain digestion of mucosa and pancreas did not release all heparin from the tissue, suggesting that the protein to which heparin is linked is not readily accessible to the enzyme.
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PMID:Glycosaminoglycans from Ateroid and bovine duodenal mucosa and pancreas. 5 31

Early effects of lipolysis on the structure of chylomicrons in vitro were studied in rat chylomicrons incubated with purified bovine mild lipoprotein lipase at pH 8.1. The amount of the albumin added to the incubation medium was limited so that free fatty acids (FFA) and partial glycerides formed during lipolysis would accumulate in the chylomicrons. The structures visualized in lipolyzed chylomicrons was found to be affected by pH during preparation of specimens for microscopy, whether fixed with OsO4 and sectioned, or stained with sodium phosphotungstate and examined as whole mounts. Circular aqueous spaces were present in the triglyceride core of lipolyzed chylomicrons processed at pH 8.1 and 7.4. Sometimes the spaces contained aggregates of osmiophilic material and whorls of bilayered lamellae. The spaces were replaced by lamellar structures having a periodicity of 40 A, in chylomicrons processed at pH 5.5, and the spaces and lamellae were both absent at pH 3.0. The findings indicate that these spaces were lined by a lipid monolayer which formed bilayered lamellae under certain conditions. It is concluded that the monolayer lining the aqueous spaces is an inward extension of the chylomicron surface film produced by the accumulation and movement of lipolytic products, FFA and partial glycerides, in the interfacial plane between core triglyceride and water.
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PMID:Retention of lipolytic products in chylomicrons incubated with lipoprotein lipase: electron microscope study. 5 12

Lipoprotein lipase activity was detected and characterized in the fat body of Triatoma brasiliensis one of the vector of Chagas' disease. The enzyme activity was close to a free fatty acid production of 47 mumol FFA mg protein-1-h-1 when assayed in the complete system. 2. The enzyme presented maximum activity at pH 8.5. It appeared to be activated by heparin (2 U/ml) and to require a cofactor (rat serum lipoproteins) when assayed with simple triglyceride emulsions. The requirement for a FFA acceptor (albumin or CaCl2) was also observed. 3. Inhibition of enzyme activity by pyrophosphate, HDB, protamine sulphate and 1 m NaC1 indicated further that the enzyme from fat body of T. brasiliensis had the characteristic features of lipoprotein lipase from other sources.
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PMID:Lipoprotein lipase in the fat body of Triatoma brasiliensis. 6 Sep 18

Some physiologic aspects of the mobilization and fate of free fatty acids are reviewed. The molecular mechanism of the activation of hormone-sensitive lipase in adipose tissue is then discussed. Recent evidence established that hormone-sensitive lipase, concerned with fat mobilization, is both functionally and immunochemically distinct from lipoprotein lipase, concerned with uptake of plasma triglycerides. Lipoprotein lipase activity is not altered by cyclic AMP-dependent protein kinase. The latter enzyme enhances not only triglyceride hydrolase but also monoglyceride, diglyceride and cholesterol ester hydrolase activities in chicken adipose tissue. Finally, it is shown that the activation of all four acyl hydrolases is reversible, the deactivation being magnesium-dependent. Protein phosphatase fractions from heart and liver active against phosphorylase a can reversibly deactivate adipose tissue hormone-sensitive lipase, implying a low degree of substrate specificity for lipase phosphatase.
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PMID:Hormone-sensitive lipase of adipose tissue. 6 71

Activatable cholesterol esterase and triacylglycerol lipase of rat adrenal were 58-69% recovered in the 100 000 X g supernatant fraction. Activatable triacylglycerol lipase activity was differentiated from the activity of acid lipase and lipoprotein lipase also found in this fraction. Cholesterol esterase was activated 39.7 +/- 13.6% (S.D.) and triacylglycerol lipase 11.9 +/- 2.9% in a reaction dependent on ATP, cyclic AMP, and protein kinase. The two activities were shown by differential inhibition by an organophosphate, and by partial separation on salting out, to be largely due to separate enzymes. The two enzymes bound tightly to substrate emulsions with quantitatively similar distribution between competing emulsions, suggesting concerted binding. Coinciding gel filtration patterns reinforced, The hypothesis of a lipase complex. Cholesterol esterase comprised a major component of higher apparent Km for substrate and molecular weight 3-10(5)-6-10(5) by gel filtration and a minor component of lower apparent Km and heterogeneous molecular weight above 1 million, which was found mostly in complex and lipid.
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PMID:Activatable cholesterol esterase and triacylglycerol lipase activities of rat adrenal and their relationship. 6 45

Clearance of plasma-triglycerides and activity of lipoprotein lipase in adipose tissue were studied in six hypertriglyceridaemic patients before and after a week of clofibrate therapy (2 g/day). Plasma-triglycerides decreased significantly from 6.85 +/- 1.1 to 2.66 +/- 0.29 mmol/l and triglyceride clearance increased significantly from 1.3 +/- 0.2 to 2.4 +/- 0.4%/min. There were concomitant significant increases in heparin-releasable lipoprotein lipase (95 +/- 16 to 181 +/- 34 nmol free fatty acids/10(6) cells/h) and in extractable lipase (88 +/- 14 to 179 +/- 28 nmol free fatty acids/10(6) cells/h). It is concluded that an important effect of clofibrate may be to increase the levels of adipose-tissue lipoprotein lipase and thereby improve the clearance of plasma-triglycerides.
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PMID:Clofibrate increases lipoprotein-lipase activity in adipose tissue of hypertriglyceridaemic patients. 7 12


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