Showing papers on "Lipase published in 1970"
TL;DR: Only apoLP-glu is able to stimulate LPL activity in the absence of phospholipid and, in the presence of phosphoipid, increases activity twelvefold over baseline levels.
634 citations
TL;DR: It is suggested that the changes in lipoprotein lipase activity of adipose and mammary tissues that occur during late pregnancy and lactation serve to divert dietary lipid from storage in adipose tissue to mammary glands for milk formation.
264 citations
TL;DR: A purified rabbit skeletal muscle adenosine 3',5'-monophosphate (cyclic AMP)-stimulated protein kinase enhanced lipolytic activity in adipose tissue homogenates and it is inferred that this effect is due to the phosphorylation and activation of a lipase in a system analogous to that involved in the activation of muscle glycogen phosphorylase.
201 citations
TL;DR: It could be tentatively concluded that the susceptibility of the 1-acyl ester bond to lipase is influenced by the type of bond present at the 2-position, similar to that of phosphatidylcholine.
118 citations
Journal Article•
108 citations
TL;DR: The results indicate that the cyclic AMP-mediated activation of hormone-sensitive lipase in adipose tissue involves a protein phosphorylation step.
Abstract: Brief incubation of partially purified preparations of hormone-sensitive lipase from rat epididymal fat pads with ATP, Mg++, cyclic adenosine 3′:5′-monophosphate and rabbit muscle protein kinase (phosphorylase b kinase kinase) resulted in enhancement of lipolytic activity (44-93%). Little or no activation was observed when either the cofactor mixture or the protein kinase was omitted. When the fat pads were incubated with epinephrine prior to homogenization, addition of kinase and cofactors to the soluble supernatant fraction caused no activation whereas good activation was obtained in preparations from paired fat pads not exposed to epinephrine. The results indicate that the cyclic AMP-mediated activation of hormone-sensitive lipase in adipose tissue involves a protein phosphorylation step. Whether the lipase itself is phosphorylated and thus activated or whether the protein kinase is activating a mediating enzyme, in analogy with its action in the glycogen phosphorylase system, remains to be determined.
106 citations
TL;DR: Using a preparation of hormone-sensitive lipase purified approximately 100-fold from rat adipose tissue cytosol, it was shown that activation can be effected in the presence of protein kinase, cyclic-3′,5′-adenosine monophosphate, ATP and Mg++.
88 citations
TL;DR: It is concluded that the resistance of unsaturated or branched acids is due to steric hindrance during the formation of the activated complex, and the saturated C4-chain seems to be optimally adaptable to the enzyme.
85 citations
TL;DR: A Penicillium roqueforti strain produced maximal amounts of lipase when grown in 0.5% casitone-1% Proflo broth, pH 5.5, at 27°C, and was thermolabile, being inactivated completely within 10 min at 50°C.
Abstract: SUMMARY: A Penicillium roqueforti strain produced maximal amounts of lipase when grown in 0.5% casitone-1% Proflo broth, pH 5.5, at 27°C. Addition of butteroil, com oil or olive oil to the growth medium inhibited the lipase production. Under pH stasis the partially purified lipase of P. roqueforti had an optimum pH of 8.0 and an optimum temperature of 37°C. Maximum lipolytic activity occurred with 5% butteroil emulsion as the substrate. Manganese chloride and magnesium chloride stimulated the enzyme activity. Calcium, sodium and potassium sale had no appreciable effect on lipolysis; silver, mercury and zinc salts were inhibitory. The lipase was thermolabile, being inactivated completely within 10 min at 50°C. The lipase hydrolyzed tributyrin, tricaprylin, tricaprin, tripropionin and triolein in decreasing order.
82 citations
76 citations
TL;DR: The pH profile obtained for enzymes in rat liver homogenate which hydrolyze glycerol esters of decanoic acid shows two distinct peaks of activity, one at pH 5 to 5.2 and the other at pH 8.6 to 9.8, where Lysosomal lipase is strongly inhibited by certain sulfhydryl reagents.
TL;DR: Compared with atherogenic diet-fed animals injected with saline, the severity of atherosclerosis and the incorporation of free fatty acids into the aortic wall were reduced and there was no change in the elevated plasma cholesterol levels.
TL;DR: A high level of lipoprotein lipase activity was demonstrable in the S 105 fraction when fat pads from fed rats were used and the enzyme was stable even in the absence of EDTA.
TL;DR: The reaction was studied by incubation of fatty acid with S-adenosylmethionine-methyl-14C and isolation of the labeled ester and some methyl ester was formed when phospholipids were added to the incubation mixture, presumably because lipase action liberated fatty acids which could serve as substrates.
TL;DR: High negative correlation between log plasma lipoprotein lipase activity and log triglyceride concentration in very low density lipoproteins was observed and a considerable decrease in enzyme activity and a marked increase in serum triglycerides was observed.
TL;DR: Results obtained on the first and subsequent days of hospitalization clearly indicated that methods for lipase determination in which an emulsion-type substrate is used are of the greatest aid in diagnosing pancreatitis.
Abstract: Sera of 19 individuals with clinically established pancreatitis were analyzed for lipase activity on emulsion-type and aqueous substrates. Serum amylase concentrations were compared. Results obtained on the first and subsequent days of hospitalization clearly indicated that methods for lipase determination in which an emulsion-type substrate is used are of the greatest aid in diagnosing pancreatitis (90 to 92% of patients with pancreatitis had supranormal results). Amylase determinations were nearly as useful as an index (78% correlation), but "lipase" values obtained with methods in which aqueous substrates are used had limited clinical usefulness (29 and 32% correlation). Serum lipase elevations in cases of pancreatitis were generally greater than amylase elevations, with some exceptions. Serum lipase should be determined with a method in which emulsion-type substrates are used. Lipase and amylase values supplement one another.
TL;DR: Determination of glycerol release in the assay system has been shown to have advantages compared with titration of fatty acids released and there was a lack of reproducibility of the substrate when different lots were used.
Abstract: A method for quantitative determination of heparin released lipoprotein lipase (LPL) activity has been developed. The importance of standardization of substrate and albumin in the assay system has been investigated. Determination of glycerol release in the assay system has been shown to have advantages compared with titration of fatty acids released. Enzyme plasma samples frozen for four months decreased in activity. The method seemed to be specific for emulsified triglycerides and the LPL activity was 98% inhibited by 1 M NaCl. However, there was a lack of reproducibility of the substrate when different lots were used. Analytical error of the method was approximately 5% and there was good reproducibility.
TL;DR: In this article, a strain of the entomophagous fungus Beauveria bassiana was cultivated under stationary and submersed conditions, and the presence of chitinase, cellulase, proteases, and lipase was ascertained.
TL;DR: The specific activity of the 15-40% ammonium sulfate fraction prepared from fat cells exposed to epinephrine and glucagon was greater than that from portions of the same cell pool not exposed to hormones.
TL;DR: Results indicate that the lipolytic enzymes found in the cell envelopes are mostly located in the plasma membrane.
Abstract: 1. The existence of phospholipase and lipase activities in the isolated cell envelopes of baker's yeast was demonstrated. 2. The content of phospholipase was found to be markedly higher than that of lipase. 3. After partial enzymic digestion of the isolated cell envelopes, the bulk of the lipolytic activities was recovered in the sedimentable preparations, which consisted of the fragments of the plasma membrane. 4. During repeated washings, the lipase was completely released from the cell envelopes, as were also the bulk of the lipid components and most of the Mg2+-dependent adenosine triphosphatase, an enzyme connected with the plasma membrane. The phospholipase was more firmly bound to the preparation but not so firmly as the external saccharase. 5. These results indicate that the lipolytic enzymes found in the cell envelopes are mostly located in the plasma membrane.
Patent•
08 Jan 1970
TL;DR: In this article, modified phosphatides of improved emulsifying power and suitable for use as anti-spattering agents in margarine are obtained by the partial hydrolysis of a vegetable phosphatide with an enzyme preparation containing lipase and phospholipase A until at least 2 percent and less than 15 percent of lysophosphatides are formed, and removal of free fatty acids by solvent extraction.
Abstract: Modified phosphatides of improved emulsifying power and suitable for use as anti-spattering agents in margarine are obtained by the partial hydrolysis of a vegetable phosphatide with an enzyme preparation containing lipase and phospholipase A until at least 2 percent and less than 15 percent of lysophosphatides are formed, and removal of free fatty acids by solvent extraction.
TL;DR: Starting from 3-sn-phosphatidylcholines carrying a 14C-labeled unsaturated fatty acid ester at the 2-position this method turned out to be very suitable for the preparation of unsaturated 14C -labeled 2-monoacyl choline phosphoglycerides.
Journal Article•
TL;DR: The effect of various antibiotics on the rate of hydrolysis of an olive oil emulsion by hog pancreatic lipase was studied by potentiometric titration.
TL;DR: Hypertriglyceridaemia was produced in rats by the intravenous infusion of Intralipid emulsion or of very low density rabbit or human lipoproteins (VLDL) and resulted in a marked decrease in epididymal adipose tissue lipoprotein lipase activity and in an increase in heart enzyme activity.
Abstract: Hypertriglyceridaemia was produced in rats by the intravenous infusion of Intralipid emulsion or of very low density (d < 1.006) rabbit or human lipoproteins (VLDL). Lipoprotein lipase activity was assayed, in tissues removed at the end of infusion, on serum-activated mono- and triolein emulsions at pH 8.6. Hypertriglyceridaemia resulted in a marked decrease in epididymal adipose tissue lipoprotein lipase activity and in an increase in heart enzyme activity. These changes were evident with both mono- and triolein substrates. The effects on adipose tissue enzyme activity seemed roughly dependent on the triglyceride (TG) level and, relative to TG elevation, were most pronounced in the case of VLDL infusion. Serum lipoprotein lipase activity, measured in the absence of heparin, was considerably increased suggesting that the TG-rich material “leached” the adipose tissue enzyme into the circulation. Leaching of lipoprotein lipase from adipose tissue by Intralipid emulsion or VLDL was also demonstrated in an in vitro system devoid of heparin. Contact with the TG-poor, 1.006 < d < 1.063, lipoprotein induced only a small loss in adipose tissue lipoprotein lipase activity, either in vitro or in vivo.
Intracellular lipolytic activity toward mono- and triolein, measured in adipose tissue and heart homogenates at pH 7.2 in the absence of serum, was not significantly affected by TG elevation. Thus, the observed changes in lipoprotein lipase activity seem unrelated to the intracellular lipolytic activity.
It is suggested that the low adipose tissue lipoprotein lipase activity and the retarded TG removal observed in certain hypertriglyceridaemic conditions may be secondary to the increased supply of TG-rich lipoproteins.
TL;DR: An extracellular lipase (glycerol ester hydrolase, EC 3.3) has been isolated from the culture medium of Pseudomonas aeruginosa and is capable of rapidly degrading the lipoprotein fractions of human serum.
TL;DR: An intracellular glycerol ester hydrolase (lipase) from Propionibacterium shermanii was recovered from cell-free extracts and purified by ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography on diethylaminoethylcellulose.
Abstract: An intracellular glycerol ester hydrolase (lipase) from Propionibacterium shermanii was recovered from cell-free extracts and purified by ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography on diethylaminoethylcellulose. Maximum enzyme activity was observed at pH 7.2 and 47 C when an emulsion of tributyrin was used as substrate. The enzyme was stable between pH 5.5 and 8. Heating the enzyme solution at 45 C for 10 min resulted in a 75% decrease in activity. Maximum rate of hydrolysis of triglycerides was observed on tripropionin, followed in order by tributyrin, tricaproin, and tricaprylin. The lipase was strongly inhibited by mercury and arsenicals, but specific sulfhydryl reagents had little or no inhibiting effect on the enzyme activity. The enzyme also showed some esterase activity, but the hydrolysis of substrates in solution was small as compared to the hydrolysis of substrates in emulsion.
TL;DR: It is demonstrated that only post-heparin serum from the rat developed increasing lipoprotein lipase activity when increasing concentrations of heparin were added to the assay system.
Abstract: Injection of heparin into a number of animal species releases lipoprotein lipase into the circulation. We have studied the effect of heparin added in vitro to the lipase activity in post-heparin serum from six mammalian species. With the exception of man, all animals were studied under anesthesia. Our results demonstrate that only post-heparin serum from the rat developed increasing lipoprotein lipase activity when increasing concentrations of heparin were added to the assay system. Heparin decreased activity in the other species. These results prompted us to test the effect of adding rat serum to post-heparin serum from the other species in the presence of increasing concentrations of heparin. Rat serum stimulated lipoprotein lipase activity markedly. In guinea pigs, post-heparin serum activity increased 2,700% at a heparin concentration of 1.0 U/ml in the assay system. This effect may be related to the extremely low level of high-density lipoprotein in the guinea pig and the presence of a unique high-density lipoprotein in the rat.
TL;DR: In this article, a large amount of enzymatic activity was demonstrated in cells of the fundic portion of the glandular stomach of animals fed with 2 ml of olive oil 20 min before death.