Showing papers on "Lipase published in 1968"

Chemically coupled enzymes

Abstract: 1283958 insolubilized enzymes CORNING GLASS WORKS 3 Sept 1969 [5 Sept 1968] 43514/69 Heading C3H An insolubilized enzyme comprises an enzyme coupled covalently to an inorganic carrier having available hydroxyl or oxide groups, said enzyme being coupled to the carrier by means of an intermediate silane coupling agent wherein the silicon portion of the molecule is attached to the carrier and the organic portion of the molecule is attached to the enzyme. The enzyme may be papain, ficin, pepsin, trypsin, chymotrypsin, bromelin, keratinase, Bacillus subtilis alkaline protease, cellulase, amylase, maltase, pectinase, chitinase, lipase, cholinesterase, lecithinase, alkaline or acid phosphatase, ribonuclease, desoxyribonuclease, arginase, asparaginase, glutaminase, urease, glucose oxidase, catalase, peroxidase, lipoxidase, cytochrome reductase, glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase, transmethylase or phosphopyruvic transphosphorylase. The carrier may be porous glass, colloidal silica, wollastonite, dried silica gel, bentonite, alumina, hydroxy-apatite, or nickel oxide.

Clearing-factor lipase in adipose tissue. A possible role of adenosine 3',5'-(cyclic)-monophosphate in the regulation of its activity.

Abstract: 1. The rise in clearing-factor lipase activity that occurs when epididymal fat bodies from starved rats are incubated in appropriate media in vitro is inhibited in the presence of 6-N-2′-O-dibutyryl-3′,5′-(cyclic)-AMP (1mm). 2. Inhibition occurs at a concentration of glucose in the incubation medium of 1·3mg./ml. or less, but not at a glucose concentration of 2·4mg./ml., unless caffeine (1mm), an inhibitor of 3′,5′-(cyclic)-nucleotide phosphodiesterase, is also present. Caffeine (5mm) alone inhibits the rise in clearing-factor lipase activity at a glucose concentration of 2·4mg./ml. of medium. 3. The concentration of free fatty acids in the epididymal fat bodies normally falls during incubations in vitro as the rise in clearing-factor lipase activity occurs. In the presence of 1mm-6-N-2′-O-dibutyryl-3′,5′-(cyclic)-AMP, however, either the tissue free fatty acid concentration is increased or it does not fall to the same extent. The concentration of glucose in the incubation medium is important in determining the direction and extent of the changes in tissue free fatty acid concentration that occur in the presence of 6-N-2′-O-dibutyryl-3′,5′-(cyclic)-AMP. 4. Free fatty acid concentrations in epididymal fat bodies in vivo rise as the clearing-factor lipase activity of the tissue falls during starvation. 5. The possibility that the concentration of 3′,5′-(cyclic)-AMP in adipose tissue may regulate clearing-factor lipase activity, and that the regulation may occur through effects of the nucleotide on tissue free fatty acid concentrations, is discussed.

Glycerol Ester Hydrolase Activity of Lactic Acid Bacteria

Abstract: Seventeen strains of lactic acid bacteria were assayed for their glycerol ester hydrolase activity by using an improved agar-well technique, and eight strains by determining the activity in cell-free extracts using a pH-stat procedure. All cultures tested showed activity and hydrolyzed tributyrin more actively than they did tricaproin. The cell extract studies demonstrated that the cells contained intracellular esterases and lipases. The culture supernatant fluid was without activity. The lipase and the esterase differed in their relative activity to each other in the different extracts and in the ease by which they could be freed from the cellular debris. It is suggested that the lipase of these organisms is an endoenzyme and the esterase an ectoenzyme.

Relationship between lipase and esterase

Abstract: There are at least two sites on the lipase which are concerned with catalysis: the catalytic site and the hydrophobic recognition site (lipid-binding site). The recognition site may be destroyed by mild proteolytic digestion, but the catalytic site may not be changed by this treatment. Mild treatment with trypsin caused change in the catalytic properties of hepatic triglyceride lipase; the water-insoluble ester-hydrolyzing activity of hepatic triglyceride lipase decreased, whereas the water-soluble ester-hydrolyzing activity did not change. After proteolytic digestion, hepatic triglyceride lipase resembles esterase since it hydrolyzes the water-soluble substrate better than the water-insoluble substrate. Conversely, esterase was converted to lipase by treatment with phospholipid. Cardiolipin in a concentration-dependent fashion enhanced triolein-hydrolysis of human serum carboxylesterase and this effect was associated with a dose-dependent decrease in water-soluble tributyrin hydrolysis. Based on these results, we propose the hypothesis that lipase and esterase have similar catalytic sites and that addition of a hydrophobic recognition site to esterase causes conversion of esterase to lipase (Fig. 9).

Clearing-factor lipase in adipose tissue. Studies with puromycin and actinomycin

Abstract: 1. When adipose tissue from starved rats is incubated in a medium containing glucose, insulin, heparin and actinomycin (5μg./ml.) the total clearing-factor lipase activity of the system increases at least tenfold over a period of 9hr. In the absence of actinomycin, enzyme activity also increases, but to a lesser extent and for only about 3hr. Some enzyme activity appears in the incubation medium in both the presence and the absence of actinomycin. 2. When the glucose and insulin of the incubation medium are replaced by pyruvate and heparin is omitted, an increase in the total clearing-factor lipase activity in the presence of actinomycin still occurs, but only after a lag of several hours. When only heparin is omitted from the medium, the rise in enzyme activity begins immediately, but there is a shoulder in the time-course curve after a few hours. In the absence of heparin, little enzyme activity appears in the incubation medium. 3. The increases in enzyme activity in the presence of actinomycin are prevented if puromycin (0·5mg./ml.) is present in the incubation medium. 4. Catecholamines and corticotrophin inhibit the increase in enzyme activity caused by actinomycin. 5. The clearing-factor lipase activity of adipose tissue from fed animals declines with a half-life of between 1 and 1·5hr. when the tissue is incubated in the presence of puromycin. The clearing-factor lipase activity of adipose tissue from starved animals is stable under similar circumstances, as is the raised activity found after such tissue has been incubated in the presence of actinomycin. 6. Clearing-factor lipase extracted from adipose tissue of fed animals is less stable in solution than that extracted from the tissue of starved animals after this has been incubated in the presence of actinomycin.

Lipase Activity of Mucor pusillus

Abstract: Two strains of Mucor pusillus were examined for their ability to synthesize lipase in a complex medium used in the production of milk-clotting protease. Lipase activity of both strains reached maximal after 6 days of incubation under submerged conditions at 35 C. Lipase secreted into the medium hydrolyzed butterfat and vegetable lipids, as well as selected synthetic triglycerides. About 50% of lipase activity was destroyed after a 45-min heat treatment at 58 C.

Intracellular distribution of lipolytic activity in the female gametophyte of germinating Douglas fir seeds.

Abstract: Acid (pH 5.2) and neutral (pH 7.1) lipase activity was studied in order to localize the sites of lipolysis in cellular fractions of catabolic organ of Douglas fir seed. Cellular particles were separated by differential centrifugation of the tissue homogenate and identified by electron microscopy. Emulsified native neutral lipids were provided as a substrate to protein body, mitochondrial, microsomal and soluble fractions, and endogenous lipids were used as a substrate for light and heavy fat body fractions. Little difference was observed in average specific activity of the two enzyme systems in dry seeds, but acid lipase activity increased sevenfold and neutral lipase activity fourfold during germination. Highest specific activity of both enzyme systems was found to be associated with the heavy fat bodies and the soluble fraction. Heavy fat bodies contained an ample quantity of endogenous substrate while the soluble fraction consisted of little substrate. Experimental data indicated that the soluble fraction was the source of lipases, and the heavy fat bodies were the site of in situ lipolysis.

Studies on the specificity of a lipase system fromGeotrichum candidum

Abstract: The lipase system fromGeotrichum candidum preferentially hydrolyzed oleic acid, regardless of position, from the four possible racemic triglycerides containing oleate and palmitate. The rate of hydrolysis of these glycerides was most rapid when the substrate contained two moles of oleate. This acid was also preferentially released from a series of triglycerides containing oleate and two moles of a saturated fatty acid. The chain length of the latter did not alter the specificity for oleate.Equimolar quantities of oleic and linoleic acids were released when triolein and trilinolein (equimolar mixture) were hydrolyzed by this lipase. No differentiation between oleate and palmitoleate was observed when racemic glyceryl 1-palmitoleate-2,3-dioleate was the substrate. However, only 7.2 M%cis-vaccenic acid was released from glyceryl 1-cis-vaccenate-2,3-dioleate and 5.4 M% petroselinic acid from glyceryl 1-palmitoleate-2,3-dipetroselinate. It therefore appears that the enzyme may be specific forcis-9-unsaturation as well as forcis-9,cis-12-unsaturation. When specificity was assumed, the fatty acid compositions of the diglycerides obtained from digestions withG. candidum were close to theoretical.

An Evaluation of Fluorometric Substrates for Lipase

Abstract: The results of a complete study of 12 substrates for lipase indicated 4-methyl umbelliferone heptanoate to be the best substrate for the analysis of this enzyme. Using this ester, from 0.000020 to 0.066 units per ml. of porcine pancreas lipase can be determined with an accuracy and precision of about 1.5%. Analysis is performed by a direct initial reaction rate method in 2–3 minutes.

Specificity of the agglutinin in extracts of wheat germ.

Abstract: EXTRACTS of wheat germ prepared to contain lipase have been shown to have the additional property of agglutinating mammalian cells1. This agglutinin is heat stable, and thus distinguishable from the lipase, which is destroyed by heating to 65° C. Aub et al. suggested that the agglutinin would agglutinate tumour cells more strongly than the equivalent normal cell1–3. The implication that extracts of wheat germ contain an agglutinin specific for tumour cells is not upheld by the experiments described here, and which involve the ability of extracts of wheat germ to agglutinate red cells and to produce mixed cell agglutination, and the ability of various sugars and salivas to inhibit this agglutinin. Wheat germ lipase (10 mg/ml., Sigma and Calbiochem) was heated at 65° C for 15 min to destroy lipolytic activity1; the preparation was centri-fuged for 10 min at 3,500 r.p.m. to remove the denatured protein, and kept frozen at −20° C.

A new rapid method for the determination of serum lipase.

Abstract: A new method is described for the determination of serum lipase using olive oil as substrate, and photometric, copper soap analysis for the measurement of fatty acids formed. The great sensitivity of this technic for measurement of the fatty acids permits a 30-min. incubation time and the use of 0.1 ml. serum. The reaction is zero order for this time period. Other aspects of the enzyme kinetics were studied and the normal values determined.

Suitability ofGeotrichum candidum lipase for the stereospecific analysis of some triglycerides.

Abstract: A procedure is described for determining the stereospecific structure of triacid triglycerides containing oleic acid. The method utilizes the unique specificity of the lipase system fromGeotricum candidum for hydrolyzing fatty acids which containcis-9-unsaturation.

Lipolytic Activity of Human Cutaneous Bacteria

Abstract: SUMMARY: Forty-two strains of Corynebacterium acnes were compared with 20 strains of staphylococci and 10 of lipophilic diphtheroids for their lipolytic action on 14 substrates and for Tween 80 hydrolysis. All strains were isolated from normal human skin. One lipophilic diphtheroid and 33 C. acnes strains hydrolysed tributyrin. Forty-nine bacillary strains hydrolysed Tween 80. None of the other substrates was degraded. C. xerosis atcc 373 and Propioni-bacterium acnes atcc 11828 acted on tributyrin. P. acnes also hydrolysed Tween 80. The staphylococci did not act on Tween 80 but attacked tributyrin, triolein, trilinolenin, trilinolein and oil emulsions. Some cocci acted on tricaprylin, tricaprin and trilaurin; no lipolysis by this group was observed of trimyristin, tripalmitin or tristearin. Pancreatic lipase, tested by the penicylinder diffusion method for comparison, was active on the same substrates, as were the cocci. The addition of glucose, lactate and urea to media did not inhibit lipolysis by the cocci. Sodium oleate inhibited pancreatic lipase action on triolein and cottonseed oil but not on the hydrolysis of tributyrin. Coccal lipase action was not inhibited by oleate. All 74 test strains were uniformly inhibited by neomycin 5–10 μg./ml. Gram-positive cocci rather than C. acnes appear primarily responsible for bacterial lipase activity on human skin.

Lipids and Related Substances Inducing the Lipase Production by Candida paralipolytica

Abstract: Sir: We can hardly find convincing evidences for inductive biosynthesis of lipase by microorganisms. Candida paralipolytica was isolated from soil as a potent lipase producer.1) Cultural con ditions for the industrial production of the lipase2) and essential activator requirements of the lipase3•`5) have been studied already. In this communication, we show that lipid material is necessary to the lipase production by C. paralipolytica. The yeast was cultured with shaking at 26.5°C for 24 hr. The synthetic medium was composed of 2%(w/v) of glucose, 0.2% of urea, 0.6°c of KH2PO4, 0.2% of K2HPO4, 0.1% of KCl, 0.05% of MgSO4.7H20, 0.001% of FeCl3 and 400ƒÊg/liter of thiamine.HCl. Lipids or related substances were added to this medium before the start of cultivation. The growth of the yeast was measured by