Showing papers on "Lipase published in 1974"
01 Jan 1974
TL;DR: This chapter describes a method for determining triglycerides using enzymatic hydrolysis, including the principle, reagents, solutions, and optimum conditions used in it, which has its own accuracy, precision, and specificity.
Abstract: Publisher Summary Serum triglycerides can be specifically and quantitatively hydrolyzed by enzymes. Lipases hydrolyze triglycerides only if the substrate is present as an emulsion. The lipase activity is proportional to the surface areas of the emulsion particles. Serum triglycerides are present as a quasi-solution in which they are bound to albumin; consequently, no measurable cleavage is observed with pancreatic lipases or a large number of other lipases. The lipase from Rhizopus arrhizus hydrolyzes serum triglycerides quantitatively to glycerol and fatty acids. This chapter describes a method for determining triglycerides using enzymatic hydrolysis. It reviews the entire procedure of this method, including the principle, reagents, solutions, and optimum conditions used in it. The chapter also reviews the preparation of the solutions used in the method and the stability of these solutions. The method has its own accuracy, precision, and specificity. However, there are some sources of error in the method as well.
941 citations
TL;DR: In 12 patients with hyperchylomicronemia, protamine-inactivated lipase activity was markedly reduced, whereas protamines-resistant lipase was below normal in only 1.5 patients, indicating the importance of distinguishing between lipases of hepatic and extra-hepatic origin in the measurement of postheparin lipolytic activity.
Abstract: An assay has been developed for specific measurement of two different lipase activities in postheparin plasma. Lipoprotein lipase, derived from extrahepatic sources, is measured as protamine-inactivated lipase activity; hepatic lipase activity is protamine-resistant under the conditions of this assay. In 100 normal subjects, both enzyme activities were noted to be related to age and sex. Protamine-resistant lipase, which comprised 46-95% of the total activity, was highest in men over 18. Protamine-inactivated lipase activity was greatest in younger males and was age-correlated in women, doubling between the second and sixth decades.
In 12 patients with hyperchylomicronemia, including five previously shown to have familial type I hyperlipoproteinemia, protamine-inactivated lipase activity was markedly reduced, whereas protamine-resistant lipase was below normal in only 1. The results were not due to lack of plasma activator, presence of plasma inhibitor, or diet, and the deficiency was not overcome by increasing the provoking dose of heparin from 10 U to 75 U/kg. Mean values for both lipase activities were not reduced in 32 other patients with hyperchylomicronemia, nine with “floating beta” lipoproteins (type III hyperlipoproteinemia), and 23 with hyperprebetalipoproteinemia (type IV). Mean protamine-resistant lipase activity was below normal in a group of four women with hypothyroidism, in whom protamine-inactivated lipase was not reduced. Both of the lipase activities were capable of hydrolyzing lipid in very low-density lipoproteins, but the relative rate of hydrolysis of chylomicrons by protamine-resistant lipase was markedly limited. These results indicate the importance of distinguishing between lipases of hepatic and extra-hepatic origin in the measurement of postheparin lipolytic activity.
451 citations
TL;DR: Bile salt caused a more than 10-fold increase of the maximal reaction rate when p-nitrophenyl acetate was the substrate and glycerol and free fatty acids were the major products formed during the reaction.
147 citations
TL;DR: Two lipases were found in extracts from castor bean (Ricinus communis L.) endosperm, one of which was present in dry seeds and displayed high activity during the first 2 days of germination, and the other with an alkaline pH optimum, which was particularly active during days 3 to 5.
Abstract: Two lipases were found in extracts from castor bean (Ricinus communis L.) endosperm. One, with optimal activity at pH 5.0 (acid lipase), was present in dry seeds and displayed high activity during the first 2 days of germination. The second, with an alkaline pH optimum (alkaline lipase), was particularly active during days 3 to 5. When total homogenates of endosperm were fractionated into fat layer, supernatant, and particulate fractions, the acid lipase was recovered in the fat layer, and the alkaline lipase was located primarily in the particulate fraction. Sucrose density gradient centrifugation showed that the alkaline lipase was located mainly in glyoxysomes, with some 30% of the activity in the endoplasmic reticulum. When glyoxysomes were broken by osmotic shock and exposed to KCl, which solubilizes most of the enzymes, the alkaline lipase remained particulate and was recovered with the glyoxysomal "ghosts" at equilibrium density 1.21 g/cm(3) on the sucrose gradient. Association of the lipase with the gly-oxysomal membrane was supported by the responses to detergents and to butanol. The alkaline lipase hydrolyzed only monosubstituted glycerols. The roles of the two lipases in lipid utilization during germination of castor bean are discussed.
146 citations
TL;DR: In this paper, the authors showed that pancreatic lipase attacks both primary ester groups of triacylglycerol at equal rates, but is less active against the secondary position.
130 citations
TL;DR: The purified enzyme had the highest specific activity so far reported for a human serum-stimulated lipase, and was active against tributyrylglycerol also in the absence of exogenous serum factors.
99 citations
TL;DR: The results suggest that when precautions are taken to prevent the binding of fatty acids to the subchloroplast particles, large amounts of lipid may be removed without a marked effect on electron flow.
Abstract: A galactolipid lipase has been isolated and partially purified from the chloroplast fraction of the primary leaves of Phaseolus vulgaris var. Kentucky Wonder. The lipase hydrolyzed monogalactosyl diglyceride rapidly and phosphatidyl choline relatively slowly. Triolein and p-nitrophenyl stearate were not hydrolyzed.Spinach subchloroplast particles were excellent substrates for the lipase. Initial rates of fatty acid release from subchloroplast particles at 30 C by the lipase as high as 60 microequivalents per minute per milligram protein were observed. At completion of the reaction, about 2.7 microequivalents of fatty acid were liberated per milligram of chlorophyll in the subchloroplast particles, indicating that major amounts of lipid in the particles were rapidly attacked by the lipase.The treatment of subchloroplast particles with the lipase resulted in a rapid inhibition of light-dependent electron flow. This inhibition was largely prevented when the incubation was carried out in the presence of high concentrations of defatted bovine serum albumin. These results suggest that when precautions are taken to prevent the binding of fatty acids to the subchloroplast particles, large amounts of lipid may be removed without a marked effect on electron flow.
86 citations
TL;DR: The moldGeotrichum candidum produces an extracellular lipase, readily concentrated by removal of the culture medium in which the microorganism is grown, which has an optimum pH of 8.2, and the lyophilized powder is extremely stable, retaining activity for at least eight years when stored at-20 C.
Abstract: The moldGeotrichum candidum produces an extracellular lipase, readily concentrated by removal of the culture medium in which the microorganism is grown. The lipase is characterized by a unique, but not absolute, specificity for fatty acids containingcis-9 orcis,cis-9, 12 unsaturation, hydrolyzing both regardless of position within the triglyceride molecule. The enzyme also hydrolyzescis-9-16∶1,cis,trans-9,12-18∶2,trans,cis-9,12-18∶2, palmitoyl oleate and cholesteryl oleate. Digested at comparatively slow rates are:trans,trans-9,12-18∶2, double bond positional isomers of 18∶1 (other thancis-9), stearolic acid, oleoylpalmitate, dilinoleoyl phosphatidyl choline, and saturated acids. The enzyme has an optimum pH of 8.2, and the lyophilized powder is extremely stable, retaining activity for at least eight years when stored at-20 C. A purification of 81-fold has been achieved.
78 citations
TL;DR: A triglyceride lipase (EC 3.1.3) was purified 1200-fold from homogenates of rat liver by cosedimentation with lysosomes, detergent solubilization, selective elution from carboxymethylcellulose by lipid activator, and gradient elutions from car boxymethyl cellulose.
77 citations
TL;DR: Hormone-sensitive lipase partially purified from adipose tissue of laying hens was markedly activated by cyclic AMP-dependent protein kinase, indicating that the physiological hormone-induced activation is probably similar to or identical with theprotein kinase activation demonstrated in the cell-free preparations.
71 citations
TL;DR: The data indicate that each molecule of human triacylglycerol lipase can easily react with one molecule of bovine colipase, and less easily with two or more molecules.
TL;DR: The findings strongly suggest that the stimulation of lipolysis by hormonal treatment is the consequence of the activation of hormone-sensitive triglyceride lipase by cyclic 3',5'-AMP-dependent protein kinase.
Abstract: A partially purified hormone-sensitive triglyceride lipase of human adipose tissue was found to be activated twofold by the addition of cyclic 3',5'-AMP, ATP, and magnesium ions. Lipase activities against diolein and monoolein were not affected. Addition of protein kinase inhibitor at zero time completely inhibited activation, and this inhibition was prevented by prior addition of an excess of exogenous protein kinase (from rabbit skeletal muscle). Addition of protein kinase inhibitor during the activation step blocked the activation process without a time lag, suggesting that protein kinase operates directly on hormone-sensitive lipase. Further purification yielded a fraction free of protein kinase, and lipase activation in this fraction depended absolutely on addition of exogenous kinase. Incubation of human fat with epinephrine or isoproterenol stimulated lipolysis and caused conversion of nonactivated hormone-sensitive lipase to its activated form, as indicated by a decrease in the activation subsequently obtainable in fractions prepared from such hormone-treated tissues. These findings strongly suggest that the stimulation of lipolysis by hormonal treatment is the consequence of the activation of hormone-sensitive triglyceride lipase by cyclic 3',5'-AMP-dependent protein kinase.
TL;DR: It is suggested that intracellular lipoprotein lipase undergoes activation in association with heparin-stimulated release from fat cells.
TL;DR: The lipolytic activity in supernatant fractions of cultures of Saccharomycopsis lipolytica, Micrococcus caseolyticus, Bacillus licheniformis, and a Staphylococcus sp.
Abstract: Summary. The lipolytic activity in supernatant fractions of cultures of Saccharomycopsis lipolytica, Micrococcus caseolyticus, Bacillus licheniformis, and a Staphylococcus sp. was studied. Nutrient broth with and without emulsified olive oil was used as substrate. Optimal pH values and temperatures for the lipase produced by the 4 different micro-organisms were determined. The lipolytic activity generally reached a maximum after incubation for 2–6 days. The subsequent decrease in the lipolytic activity was associated with a high proteolytic activity only for Micrococcus caseolyticus. The lipolytic activity was decreased by the presence of olive oil in the medium. Determination of the lipolytic activity after a certain time of incubation, the maximal lipolytic activity and a time-integrated lipolytic activity are compared as estimators for the potential hydrolytic capacity of micro-organisms.
TL;DR: The finding that lipase can display a strong activity in the complete absence of substrate aggregates and interfaces is discussed in the light of current concepts concerning the mechanism of action of this enzyme.
TL;DR: Peripheral uptake of triglyceride from plasma was investigated by intravenous fat tolerance tests and by postheparin lipoprotein lipase measurements in children with different types of glycogen storage disease to speculate on the dietary treatment of hyperlipidemia in hepatic glycogenosis.
Abstract: Extract: Peripheral uptake of triglyceride from plasma was investigated by intravenous fat tolerance tests and by postheparin lipoprotein lipase measurements in children with different types of glycogen storage disease. The patients with a glucose 6-phosphatase deficiency were characterized by a significantly diminished triglyceride elimination rate (5.79 ± 2.78%/min) and 5-min postheparin lipoprotein lipase activity (40.2 ± 23 μEq fatty acid (FA)/liter/min). The patients with a deficiency of debranching enzyme showed a significantly diminished triglyceride elimination rate (4.84 ± 1.61%/min) whereas the 5-min postheparin lipoprotein lipase activities did not significantly differ from the control values (49.6 ± 27.7 μEq FA/liter/min). The patients with a deficiency of the phosphorylase system showed neither a significantly diminished triglyceride elimination rate (7.34 ± 2.65%/min) nor a diminished 5-min postheparin lipoprotein lipase activity (61.7 ± 30.1 μEq FA/liter/ min). Triglyceride elimination rates were correlated positively with plasma lipoprotein lipase activities (r = 0.55, P < 0.05). Speculation: The dietary treatment of hyperlipidemia in hepatic glycogenosis might be based on the outcome of the intravenous fat tolerance test, a low fat clearance being an indication for a low fat, high carbohydrate diet, a normal fat tolerance for a high fat low carbohydrate diet.
TL;DR: In this paper, two cutanious bacteria Corynebacterium acnes and Staphylococcus epidermidis have been partially purified and characterized to permit the screening of possible enzyme inhibitors.
TL;DR: Investigation of the influence of the amount of heparin injected on the contributions of liver and of extrahepatic tissues to the lipase activity of postheparin serum of the rat suggested that the enzyme may be in a more active state.
TL;DR: Evidence is presented for the existence of a factor in pre-heparin plasma which can cause a shift in the pH optimum to 7.6, compatible with the presence of both this enzyme and a lipase with the properties of adipose tissue lipoprotein lipase.
TL;DR: Various interfaces were found to exert a considerable accelerating effect in the lipase-p-nitrophenyl acetate-acetonitrile system.
TL;DR: A role for calcium ions as well as cyclic-AMP in the control of lipolysis is postulated.
Abstract: The reaction steps involved in the activation and inactivation of the hormone sensitive lipase have been studied in human adipose tissue. Homogenates prepared from adipose tissue shreds or isolated fat cells contained a cyclic-AMP dependant protein kinase. This enzyme was partially purified from the 100,000 g supernatant using DEAE Cellulose Column Chromatography. The activity of the purified preparation was stimulated 3-4 fold with cyclic-AMP and inhibited with progressive increases in free calcium concentration in the reaction mixture. Calcium seems to inhibit the binding of cyclic-AMP to the protein kinase regulatory units and thus abolishes cyclic-AMP stimulation. In the presence of cyclic-AMP and ATP the protein kinase phosphorylates a lipase preparation partially purified from the same tissue with synchronous increase in the lipolytic activity. Inactivation of the lipase is preceeded by its dephosphorylation by a phosphatase(s) which is present in 105,000 g supernatant. Increasing free calcium concentration between 10-8 and 10-3M produced progressive inhibition of the lipase activity. This inhibition can be attributed to a dual mechanism. First, calcium ions inhibited the protein kinase activation of the lipase. Second, calcium ions stimulated the adipose tissue phosphatase(s) and this increased the rate of inactivation of the hormone sensitive lipase. A role for calcium ions as well as cyclic-AMP in the control of lipolysis is postulated.
TL;DR: Measurement of serum amylase and lipase levels together will improve diagnostic accuracy in acute pancreatitis.
Abstract: Lipase activity was simultaneously determined with amylase activity in the sera of 30 hospitalized patients with acute pancreatitis. On admission to the study, 70% of patients with acute pancreatitis had increased serum amylase, 63% had increased lipase, and 83% had increased lipase, increased amylase, or both. All patients had either lipase or amylase increase at some time during the course of their disease. Lipase level elevation paralleled the amylase in the majority of cases. There were several instances of earlier elevation of the lipase level. The traditional thesis that lipase level elevation occurs later and lasts longer than that of amylase was not confirmed. Measurement of serum amylase and lipase levels together will improve diagnostic accuracy in acute pancreatitis. (JAMA229:47-50, 1974)
Patent•
10 May 1974TL;DR: In this paper, a method for producing blue cheese from pasteurized or heat treated milk is described, characterized by the addition to the cheese curds from which the whey has been drained, of a mixture of lipase, a Penicillium mold spore species, and salt.
Abstract: A method for producing blue cheese from pasteurized or heat treated milk, characterized by the addition to the cheese curds from which the whey has been drained, of a mixture of lipase, a Penicillium mold spore species, and salt. The Penicillium species may include Penicillium roqueforti or Penicillium glaucum, and the lipase is preferably a microbial lipase formed from Aspergilli ssp., Penicillium ssp. or Rhizopus ssp., or suitable animal lipase sources. The resultant cheese product is imparted with the appropriate blue cheese flavor with required rancidity in a greatly shortened period of time (i.e., about 2 to 4 months).
TL;DR: Like pancreatic lipase, Rhizopus lipase acts on micelles of short chain triglycerides and is inhibited by high concentrations of bile acids; however, in the presence of deoxycholate,Rhizopuslipase does not require added Ca++ for full activity.
Abstract: Rhizopus arrhizus, a mold of the mucor family, excretes an active lipase when cultured properly. This lipase has a mol wt of 43,000 and a high carbohydrate content, Upon storage at 4C in aqueous solution, lipase I is slowly converted by proteolysis to a more cationic form, lipase II, which has a lower mol wt (32,000) and no carbohydrate.Rhizopus lipase shows the same positional specificity on long chain triglycerides as pancreatic lipase; it has no preferential side chain specificity against oleic vs. palmitic acid. Like pancreatic lipase,Rhizopus lipase acts on micelles of short chain triglycerides and is inhibited by high concentrations of bile acids; however, in the presence of deoxycholate,Rhizopus lipase does not require added Ca++ for full activity.
01 Mar 1974
TL;DR: A lipase rich fraction was isolated from the cell free supernatant of 24-hour broth culture of Staphylococcus aureus B-120, grown in trypticase soy broth at 37 C.
Abstract: A lipase rich fraction was isolated from the cell free supernatant of 24 hr broth culture ofStaphylococcus aureus B-120, grown in trypticase soy broth at 37 C. Lipase from the cell free supernatant was precipitated with equal volumes of absolute ethanol. This fraction was purified further by differential precipitation at pH 8.6 and 4.3. Subsequent purification, using Sephadex G-200 and BioGel 300, yielded a preparation with 350–450-fold increase in specific activity. The purified lipase had an optimum pH of 8.5 at 37 C. The electrophoretic mobility was-7.78×10−5 cm2/volt/sec. The sedimentation coefficient for the two peaks was 2.85 and 8.5, respectively, and the mol wt was 100,000. The purified lipase hydrolyzed a variety of natural oils and fats. The amount of free fatty acids liberated from hydrogenated soybean oil (iodine value<3) was one-third compared to natural oils and fats. Gas chromatographic analysis of hydrolyzed synthetic triglyceride, with palmitic, stearic, and oleic acids at the rac 1, 2, and 3 positions, respectively, indicated that the enzyme was capable of hydrolyzing the glycerolfatty acid bonds at all three positions. The yield was 40% palmitic, 20% stearic, and 39% oleic acids. Formaldehyde, mercaptoethanol, cysteine, glutathione, and terramycin had inhibitory effects upon lipase activity while hydrogen peroxide, streptomycin, and sodium taurocholate had a stimulatory effect upon the activity.
TL;DR: Post-heparin plasma lipoprotein lipase and a triglyceride lipase of hepatic origin were partially purified in a new case of Tangier disease, finding no deficiency in either of these enzymes could be explained.
Abstract: Post-heparin plasma lipoprotein lipase and a triglyceride lipase of hepatic origin were partially purified in a new case of Tangier disease. No deficiency in either of these enzymes could ...
TL;DR: Characterization of reaction products showed that an enzyme isolated from potato tubers could act on endogenous substrates as a galactolipase but not as a lipase, and the affinity of the enzyme for methanol as acyl acceptor was higher than its affinity for water.
TL;DR: The activities of glycerol ester hydrolase, lipase, and ester enzyme were determined for whole cell preparations of Brevibacterium linens by using the pH-stat assay and the ability to hydrolyze the two esterase substrates varied independently of the level of lipase activity.
Abstract: The activities of glycerol ester hydrolase, lipase (EC 3.1.1.3) and carboxylesterase, and esterase (EC 3.1.1.1) were determined for whole cell preparations of Brevibacterium linens by using the pH-stat assay. The culture growth liquors were inactive against the three substrates, tributyrin emulsion, triacetin, and methyl butyrate. Cells washed in water had less activity than cells washed in 5% NaCl; the ratio of activities was close to 1:2 for all strains using tributyrin emulsion as the substrate. For the esterase substrates, this relationship varied widely and was strain dependent. The ability to hydrolyze the two esterase substrates varied independently of the level of lipase activity.
TL;DR: The rise in adipose-tissue clearing-factor lipase activity that results from feeding glucose to starved rats cannot be duplicated by giving equicaloric amounts of fructose or sucrose by an inability of the administered fructose and sucrose to raise the plasma insulin concentration.
Abstract: The rise in adipose-tissue clearing-factor lipase activity that results from feeding glucose to starved rats cannot be duplicated by giving equicaloric amounts of fructose or sucrose. An inability of the administered fructose and sucrose to raise the plasma insulin concentration probably accounts for this failure in enzyme response.