Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The heparin-releasable neutral lipase (EC 3.1.1.3) from rat liver is inactivated by the common preparations of collagenases (EC 3.4.24.3) used for the isolation of liver cells. We show that two collagenases purified from Clostridium histolyticum allow both the complete preservation of this lipolytic activity and a good viability of liver cells isolated by the usual perfusion protocol.
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PMID:Use of specific collagenases for the isolation of rat liver cells with preserved lipase activities. 301 Jul 71

By using a specific collagenase preparation preserving lipolytic enzymes, we could isolate intact rat liver cells with monoester lipase (MEL) and, for the first time, substantial amounts of endogenous neutral triester lipase (TEL) activities assayable as cell-bound enzymes. TEL and MEL activities were found exclusively in parenchymal cells. Virtually all TEL was located on plasma membrane from which it was rapidly released at 37 degrees C in the absence of any additive. MEL was distributed almost equally inside the cell and in the membrane, to which it was firmly attached. Infusion of heparin to the whole animal before liver exposure decreased by 80% the TEL content of parenchymal cells (a property typical of hepatic lipase) whilst MEL was unchanged. These results question the concept that heparin-releasable hepatic lipase acts at the surface of endothelial liver cells and further suggest that TEL and MEL refer to distinct catalytic entities.
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PMID:Lipolytic activities of freshly isolated rat liver parenchymal cells. 333 46

1. Incubation of intact epididymal adipose tissue from fed rats at 37 degrees in an albumin solution at pH7.4 in vitro results in rapid loss of clearing-factor lipase activity until a low activity, stable to prolonged incubation, is attained. The clearing-factor lipase activity of intact tissue from starved rats, which is initially much less than that of tissue from fed rats, is mainly stable to incubation at 37 degrees . 2. Much of the clearing-factor lipase activity of intact epididymal adipose tissue from fed rats is inactivated by collagenase. The enzyme activity of intact tissue from starved rats is not inactivated by collagenase. 3. The clearing-factor lipase activity of fat cells isolated from the epididymal adipose tissue of fed rats is stable to prolonged incubation at 37 degrees . It represents only a small proportion of the total activity of the intact tissue. In starved rats, the isolated fat cells contain a much higher proportion of the activity of the intact tissue. Their activity is also stable at 37 degrees . 4. Incubation of isolated fat cells in a serum-based medium leads to a progressive rise in clearing-factor lipase activity. Actinomycin increases the extent of this rise in activity. No rise in clearing-factor lipase activity occurs when stromal-vascular cells isolated from epididymal adipose tissue are incubated in the medium. 5. The findings indicate that less than 20% of the activity of intact adipose tissue from fed rats is retained when fat cells are isolated from the tissue by collagenase treatment. The activity that is lost could be that which normally functions in the uptake of triglyceride fatty acids by the tissue.
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PMID:Clearing-factor lipase in adipose tissue. Distinction of different states of the enzyme and the possible role of the fat cell in the maintenance of tissue activity. 430 92

All strains of Legionella pneumophila tested produced detectable levels of extracellular protease, phosphatase, lipase, deoxyribonuclease, ribonuclease, and beta-lactamase activity. Weak starch hydrolysis was also demonstrated for all strains. Elastase, collagenase, phospholipase C, hyaluronidase, chondroitinase, neuraminidase, or coagulase were not detected in any of these laboratory-maintained strains.
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PMID:Extracellular enzymes of Legionella pneumophila. 626 49

Thirty-three strains of anaerobic bacteria isolated from human clinical specimens were examined for the presence of heparinase, hyaluronidase, chondroitin sulfatase, gelatinase, collagenase, fibrinolysin, lecithinase, and lipase activities. Pronounced heparinase activity was limited to species of the genus Bacteroides. A number of species of the genera Bacteroides and Clostridium produced hyaluronidase and chondroitin sulfatase. Gelatinase, collagenase, and fibrinolysin activities were encountered in isolates of the genera Bacteroides, Clostridium, and Peptostreptococcus. All strains capable of degrading collagen also hydrolyzed other protein substrates. Lipolytic activity was minimal among these anaerobic bacteria. No specific hydrolytic activity was consistently associated with the isolates.
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PMID:Hydrolytic enzymes of anaerobic bacteria isolated from human infections. 626 57

Recent studies of hepatitis B virus suggest that polymeric human serum albumin may facilitate the attachment of the virus via albumin receptors to hepatocytes during the infectious process. If this hypothesis is correct, hepatocytes should express binding sites for polymeric albumin. We employed the red blood cell adherence test using albumin-coated red blood cells as indicator cells on frozen sections of normal human livers to demonstrate these binding sites. Hepatocytes showed binding activity for both polymeric and monomeric albumin from different species. The receptor-ligand interaction was temperature and pH dependent, Ca++ independent and not altered by mercaptoethanol treatment. The binding activity was sensitive to neuraminidase and pronase, but resistant to trypsin, lipase and collagenase digestion. These findings suggest that human hepatocytes display species-non-specific albumin binding sites, which are glycoproteins.
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PMID:Albumin binding sites of human hepatocytes. 631 67

Endothelial cells from rat epididymal fat pad capillaries were isolated from rats immediately after weaning. The cells were obtained after an initial brief incubation with collagenase under conditions of minimal breakage of cells. Adipocytes were removed by flotation and endothelial cells were then obtained as cell aggregates by fractional filtration procedures whereby intact tissue as well as free cells were removed. These aggregates were then dispersed and cultured in supplemented medium 199 whereby a monolayer of cells with a growth pattern, numerous pinocytotic vesicles, and intercellular junctions typical of endothelial cells were obtained. Minor contaminations of precursor cells to adipocytes were absent after one subculture. Here greater than 95% of the cells showed the presence of Factor VIII. Further subcultures produced nonhomogenous cells and decreasing rates of replication. The endothelial cells showed a very low rate of triglyceride synthesis and release, and collected no visible lipid upon prolonged cultures in the presence of an abundance of triglyceride substrate. They bound lipoprotein lipase from rat adipocytes, whereby the lipase was stabilized. This binding was released by heparin, and the cells did not synthesize the enzyme.
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PMID:Isolation and characterization of endothelial cells from the epididymal fat pad of the rat. 683 87

It is generally accepted that the cell population of naturally occurring and experimental atherosclerotic lesions is constituted by smooth muscle cells and non-myogenic foam cells of monocytic origin. In the present investigation we studied aortic fatty streaks from cholesterol-fed African green monkeys. In addition to the traditionally recognized cell types, the majority of the lesions examined contained intimal granulocytic cells identified by their ultrastructural characteristics and granular content as neutrophils, mast cells-basophils, and eosinophils. The neutrophils, and mast cells-basophils additionally contained numerous cytoplasmic lipid droplets. The consistent observation of these cell types in our material suggests that these granulocytic elements are part of the cell population of fatty streaks. The role of these cells is not clear as yet, but it is likely that the enzymatic activity of neutrophils such as lipase, phospholipases A and B, elastase and collagenase may play a role in the clearing of arterial lipid as well as in arterial wall remodeling. The content and release of heparin and histamine by basophils and mast cells may play a role in preventing thrombus formation and in promoting lipolysis. Eosinophil peroxidase may activate histamine release by basophils and mast cells. The cytoplasmic lipid accumulation by neutrophils, basophils and mast cells may in turn contribute to the population of foam cells in these lesions.
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PMID:The cell population of aortic fatty streaks in African green monkeys with special reference to granulocytic cells. An ultrastructural study. 711 63

There have been numerous reports suggesting the existence of two or more lipases in liver capable of hydrolyzing triacylglycerols at neutral to alkaline pH. We set out to determine if rat liver contains an alkaline triacylglycerol lipase, in addition to heparin-releasable lipase, which has an intracellular localization. We report here the results of studies concerning the pH dependence, subcellular localization and kinetic analysis of the alkaline lipase(s) of rat liver. Homogenates and cytosolic, microsomal and plasma membrane-enriched subfractions all exhibited an optimum of lipase activity at approx. pH 8.0. In no case was there evidence of multiple pH optima in the alkaline ranges of conformity to Michaelis-Menten kinetics were calculated for the microsomal (0.91 +/- 0.12 mM), cytosolic (1.55 +/- 0.38 mM) and plasma membrane-enriched (1.02 +/- 0.04 mM) subfractions. To determine if the com- and subfractions prepared from control livers with those prepared from livers perfused with collagenase. The loss (93%) of lipase activity from both the cytosolic and microsomal subfractions after collagenase perfusion was identical to the loss (93%) of activity from the homogenates, suggesting a common origin with the collagenase-sensitive alkaline lipase on plasma membrane. The characteristics of hydrolysis in vitro of triacylglycerol contained in artificial and natural substrate preparations by the alkaline lipase of rat liver were examined. The artificial substrate preparation was emulsified tri[1-14C]oleoylglycerol prepared by sonication and the natural substrate preparation was a triacylglycerol-rich lipid fraction ('liver fat') prepared from rat liver homogenates. Although the curves were complex, apparent Km values (mean +/- S.W., n = 3-6) over the limited concentration ranges of conformity to Michaelis-Menten kinetics were calculated for the microsomal (0.91 +/- 0.12 mM), cytosolic (1.55 +/- 0.38 mM) and plasma membrane-enriched (1.02 +/- 0.04 mM) subfractions. To determine if the complexity of these kinetics was related to changes in the products of lipolysis, we examined the products after incubations of plasma membrane-enriched fractions with lower and higher concentrations of triacylglycerol. In either case, the products of lipolysis were diacylglycerol, fatty acids and glycerol; no monoacylglycerol accumulated under any circumstances. At the lower concentrations of either tri[1-14C]oleoylglycerol or liver fat, most triacylglycerol hydrolyzed was degraded fully to fatty acids and glycerol. At the higher triacylglycerol concentrations, while complete degradation continued, virtually all of the increased lipolysis of triacylglycerol (over the lipolysis at the lower substrate concentrations) yielded diacylglycerol. The data indicated that the hydrolysis of diacylglycerol by the alkaline lipase of rat liver occurred at a rate slower than that of triacylglycerol. If the same enzyme catalyzes the lipolysis of both tri- and diacylglycerols, triacylglycerols would appear to be preferred...
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PMID:Evidence for the existence of only one triacylglycerol lipase of rat liver active at alkaline pH. 728 28

Active digestive enzymes are involved in the pathophysiology of acute pancreatitis. Previous studies have mainly focused on the role of trypsin in the autodigestive process. The present study compares the noxious potential of different pancreatic enzymes to damage acinar cells. Acinar cells were isolated from rat pancreas by collagenase digestion. Cell viability was studied by (1) exclusion of trypan blue, (2) release of lactate dehydrogenase, and (3) release of newly synthesized proteins identified with methionine labeled with sulfur 35. Cells were then incubated in oxygenated N-2-hydroxyethylpiperazine-N-'-2-ethanesulfonic acid-Ringer solution containing different concentrations of various active digestive enzymes. Uptake of trypan blue was the most sensitive and reliable test of cell damage when compared with release of lactate dehydrogenase or radiolabeled newly synthesized proteins. All active digestive enzymes studied caused dose-dependent cell damage. The noxious potential, however, was strikingly different for the various enzymes. Pancreatic elastase in nanomolar concentrations caused marked cell damage after 45 to 90 minutes of incubation. Lipase and chymotrypsin caused a similar damage only at micromolar concentrations, whereas even millimolar concentrations of trypsin failed to cause significant damage. The present results confirmed recent work showing that lipase and phospholipase A2 probably cause cell damage through release of free fatty acids and lysolecithin. Although activation of trypsin might be the trigger to start the activation cascade in acute pancreatitis, trypsin itself is markedly less noxious to acinar cells when compared with other digestive enzymes. Elastase by far had the greatest noxious potential of all enzymes evaluated. Studies analyzing therapeutic effects of protease inhibitors should evaluate not only the inhibitory potential against trypsin but also that against other digestive enzymes, particularly elastase.
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PMID:Active pancreatic digestive enzymes show striking differences in their potential to damage isolated rat pancreatic acinar cells. 784 75


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