Showing papers on "Lipase published in 1971"
TL;DR: Gastric lipase probably contributes to digestion of milk triglyceride in infants, as well as to hydrolysis of administered medium chain triglyceride, especially in children with decreased pancreatic lipase concentrations.
155 citations
Journal Article•
148 citations
TL;DR: Stereospecific analysis determines how the fatty acids of triglycerides are distributed over the three different positions of the glycerol as discussed by the authors, which is the special problem is the differentiation of position I-1 and L-3.
Abstract: Stereospecific analysis determines how the fatty acids of triglycerides are distributed over the three different positions of the glycerol. The special problem is the differentiation of position I-1 and L-3 of glycerol. In the presently known methods, triglycerides are first degraded to mixtures of diglycerides, either by the action of a lipase or by degradation with a Grignard reagent. The isomeric diglycerides are then resolved with the help of a stereospecific enzyme, either a diglyceride kinase or (after conversion of the diglycerides to phospholipids) a phospholipase. It is then possible to analyze or calculate the fatty acid composition for each position on the glycerol. The key to a successful stereospecific analysis is the preparation of a representative diglyceride mixture by a truly random degradation of the triglyceride. The Grignard degradation is the most reliable method, but it is not always applicable, and it is accompanied by some isomerization of glycerides. There is room for improvement in the method. Analyse of natural fats have shown most of them to be asymmetric, i.e., the composition of fatty acids in position 1 differs markedly from that of position 3. Several rules of fatty acid distribution have become apparent.
128 citations
TL;DR: The results strongly support the conclusion that hormonal activation of adipose tissue lipase is mediated by cyclic AMP, that the cyclicAMP acts via protein kinase, and that the conversion of inactivelipase is linked to enzyme phosphorylation.
115 citations
TL;DR: It is concluded that it is one of the functions of bile salts, and of proteid cofactors, to protect the native structure of lipase and to keep the oil-water interphase free from blockage by unfolded proteins.
112 citations
TL;DR: E 600, an inhibitor of lipase, largely prevented the appearance of lysolecithin and fatty acids in pancreatic microsomes and in livermicrosomes treated with pancreatic supernatant.
Abstract: The lipid composition of rough and smooth microsomal membranes, zymogen granule membranes, and a plasmalemmal fraction from the guinea pig pancreatic exocrine cell has been determined. As a group, membranes of the smooth variety (i.e., smooth microsomes, zymogen granule membranes, and the plasmalemma) were similar in their content of phospholipids, cholesterol and neutral lipids, and in the ratio of total lipids to membrane proteins. In contrast, rough microsomal membranes contained much less sphingomyelin and cholesterol and possessed a smaller lipid/protein ratio. All membrane fractions were unusually high in their content of lysolecithin (up to ∼20% of the total phospholipids) and of neutral lipids, especially fatty acids. The lysolecithin content was shown to be due to the hydrolysis of membrane lecithin by pancreatic lipase; the fatty acids, liberated by the action of lipase on endogenous triglyceride stores, are apparently scavenged by the membranes from the suspending media. Similar artifactually high levels of lysolecithin and fatty acids were noted in hepatic microsomes incubated with pancreatic postmicrosomal supernatant. E 600, an inhibitor of lipase, largely prevented the appearance of lysolecithin and fatty acids in pancreatic microsomes and in liver microsomes treated with pancreatic supernatant.
105 citations
TL;DR: With the present fast and convenient method, serum lipase appears to be a better test for pancreatitis than is serum amylase.
Abstract: Serum lipase is determined by following turbidity changes during two 1-min intervals after adding serum to an olive oil emulsion containing desoxycholate. The olive oil emulsion is simply prepared and is stable for a month under refrigeration. Our observations confirm the findings of other investigators that increases in serum lipase activity are more accentuated than increases in serum amylase activity during pancreatitis. With the present fast and convenient method, serum lipase appears to be a better test for pancreatitis than is serum amylase.
103 citations
TL;DR: It can be concluded that the Candida lipase is able to attack secondary ester groups of glycerol without the help of an isomerase.
102 citations
TL;DR: The purified enzyme had a higher specific activity than any other preparation of lipoprotein lipase described so far and was exploited for the purification of the enzyme from skim milk by affinity chromatography on a column of heparin-substituted agarose.
99 citations
TL;DR: Ananerovibrio lipolytica strain 5s, an anaerobic rumen bacterium, produced an extracellular lipase during exponential growth in batch cultures, and the enzyme was most active at pH 7.4 and at 20 to 22°; activity was enhanced by Cal2 or BaCl2 while ZnCl2 and HgCl2 were inhibitory.
Abstract: SUMMARY: Anaerovibrio lipolytica strain 5s, an anaerobic rumen bacterium, produced an extracellular lipase during exponential growth in batch cultures. The lipolytic activity was excluded from Sephadex G-200, and the purest preparations obtained contained two components when examined by electrophoresis or by ultracentrifugation and a large proportion of nucleic acid. The enzyme was most active at pH 7.4 and at 20 to 22°; activity was enhanced by Cal2 or BaCl2 while ZnCl2 and HgCl2 were inhibitory. Sodium chloride at high concentration was also inhibitory. Trilaurin was most rapidly hydrolysed of the triglycerides but diglycerides were more rapidly hydrolysed than were triglycerides.
82 citations
TL;DR: Rat and human lipase substantially free of lipase cofactor prepared by Sephadex G-100 chromatography of pancreatic juice were inhibited by sodium taurocholate and sodium tAUrodeoxycholate in concentrations above their critical micellar concentration, but if cofactor was added these bile salt concentrations stimulated lipolysis.
TL;DR: Adult rats, previously maintained on a chow containing 48 p.
TL;DR: Two well-defined S-substituted lipase derivatives were prepared: mono 5-thio-2-nitrobenzoic acid (TNB) lipase in which the SH1 group was selectively blocked by a TNB radical and diphenyl mercuric (DPM) lipases in whichThe properties of both groups suggest that they are situated in an hydrophobic region of the molecule.
TL;DR: The data support the view, however, that glycerol is obtained predominantly from 1-monoglyceride formed by isomerization, and no conclusive evidence is presented for the mechanism of hydrolysis of the monoglycerides.
TL;DR: In this paper, extracts of Salmonella typhimurium prepared by different techniques contain both soluble and particulate forms of the anthranilate synthetase-anthranilates-5-phosphoribosylpyrophosphate phosphoribosayltransferase (PR transferase) aggregate.
TL;DR: Gel filtraton and dialysis experiments demonstrate that tetracycline binds to C. acnes lipase and even more to bovine serum albumin.
TL;DR: Hydlysis of triglycerides was shown to be completely random with respect to the position of glycerol in a triglyceride and the enzyme did not hydrolyze phospholipids or cholesterol linolenate.
TL;DR: Comparison of difference spectra and after irradiation at −196° show that the photochemical electron transfer results in a shift of the absorption band of C-550 from 546 to 544 nm.
TL;DR: In rats fed SBTI, the large increase in intestinal proteolytic enzyme activity was due almost exclusively to chymotrypsin, and that in rats fed PCI was much less than in controls, reflecting an almost total inhibition of the enzymes by their inhibitors as they passed through the gut.
Abstract: SummaryExperiments were conducted to investigate the effect of dietary chymotrypsin inhibitor on pancreatic enzyme secretion in the rat, and to compare the response to that evoked by soy bean trypsin inhibitor.Potato chymotrypsin inhibitor evoked a moderately exaggerated pancreatic response compared to casein-fed controls, as demonstrated by a depletion of pancreatic trypsin, chymotrypsin, and lipase activities, and a concomitant increase in the activities of intestinal trypsin and lipase. The PCI-induced response was not nearly as pronounced as that produced by SBTI, in addition to being somewhat delayed.Intestinal trypsin activity in SBTI-fed rats, and chymotrypsin activity in PCI-fed rats, were much less than in controls—often lower than in the fasting state—reflecting an almost total inhibition of the enzymes by their inhibitors as they passed through the gut. In rats fed SBTI, the large increase in intestinal proteolytic enzyme activity was due almost exclusively to chymotrypsin.
TL;DR: A lipase which hydrolyzes triglycerides and naphthyl laurate was obtained from the broth of Corynebacterium acnes cultures by ammonium sulfate fractionation and tetracycline inhibition of the C. acnes lipase could be demonstrated at concentrations as low as 10(-6)m.
Abstract: A lipase which hydrolyzes triglycerides (tricaprylin and trilaurin) and naphthyl laurate was obtained from the broth of Corynebacterium acnes cultures by ammonium sulfate fractionation. Ca2+ and sodium taurocholate stimulated activity of the enzyme. Ethylenediaminetetraacetic acid (EDTA) did not inhibit activity of the Ca2+-activated enzyme, but lipolytic activity was inhibited by EDTA in the absence of Ca2+. Tetracycline (10−4m) produced a slight inhibition of the lipase activity with 5 × 10−5m or less showing no effect on the lipase activity. However, complete inhibition by tetracycline at 10−4m was observed for Ca2+-activated enzyme. Tetracycline inhibition of the C. acnes lipase could be demonstrated at concentrations as low as 10−6m.
TL;DR: In goat mammary tissue, glycerol-3-phosphate was a more effective acceptor of fatty acids than I -monoglycerides, and the use of glyceryl ethers as model compounds of monoglyceride showed that 2-glyceryl Ethers were more effective than I-monoglycers ethers.
TL;DR: Light-induced fluorescence yield changes and low-temperature changes were measured in spinach and Chlamydomonas reinhardi chloroplasts before and after treatment with pancreatic lipase.
TL;DR: Equimolecular mixtures of esters of long-chain fatty acids and short-chain primary alcohols are hydrolysed by pure porcine pancreatic lipase, and the composition of the acyl chains in the liberated fatty acids is compared to that of initial esters mixtures to give the relative lipolysis rates of ester groups in which the alkyl groups are different.
TL;DR: It was found that 15 or 30% dietary soybean did not significantly alter the cellular structure or weight of the pancreas (g/kg) of the adult dog and the synthesis of trypsinogen, chymotryps inogen, and lipase was temporarily impaired, but their synthesis was returned to normal.
Abstract: SummaryIn summary, 15 or 30% dietary soybean did not significantly alter the cellular structure or weight of the pancreas (g/kg) of the adult dog. The synthesis of trypsinogen, chymotrypsinogen, and lipase was temporarily impaired, but their synthesis was returned to normal. The effects of raw soybean on the dogs in this study were different from those reported in rats and chicks.
TL;DR: Sucrose gradient centrifugation has been used to examine the triglyceride lipases present in extracts of rat epididymal adipose tissue and one of these appears in the 15s region and has been identified as the active form of the "hormone-sensitive lipase" believed to be responsible for initiating the hydrolysis of tissue triglyceride stores in response to lipolytic stimuli.
TL;DR: Hydrolysis with lipase showed that the labeled short-chain acids were located in the primary positions of the glyceride glycerol and that medium- and long-chain fatty acids were Located on both primary and secondary positions ofThe glycerl moiety.
TL;DR: Six series of non‐ionic surface active polyethylene glycol ethers, whose effects on experimental tuberculosis have previously been correlated with their polyoxyethylene chain lengths, were examined for their influence on the activity of a lipase present in homogenates of normal mouse peritoneal macrophages.
Abstract: 1. Six series of non-ionic surface active polyethylene glycol ethers, whose effects on experimental tuberculosis have previously been correlated with their polyoxyethylene chain lengths, were examined for their influence on the activity of a lipase present in homogenates of normal mouse peritoneal macrophages. The surfactants are concentrated in the lysosomes of macrophages—a cell type in which the host-parasite confrontation takes place. A preparation of soy bean oil was used as triglyceride substrate; and hydrolysis at pH 4·5 was compared in the presence and absence of surfactant, the products of hydrolysis being assayed by photodensitometry of thin-layer chromatograms.
2. The compounds with short polyoxyethylene chains inhibited the release of fatty acid, compared with surfactant-free standard, more than did those with long chains; and some of the latter showed actual enhancement of release. Accumulation of monoglyceride was observed in the presence of six of the seven long-chained compounds, but with none of the seven short-chained compounds.
3. The similarity between this correlation of chain length of the surfactants with their effect on macrophage lipase activity, and the known correlation of their chain length with their effect on experimental tuberculosis, suggests a possible connection. How this connection might relate to the mechanism of the varying effects on tuberculosis is briefly discussed.
TL;DR: When concentrated dispersions of tripalmitin in Triton X-100 are added to reaction mixtures containing soluble beef liver lipase, the rate of hydrolysis of tripAlmitin increases with incubation time.