Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lipoprotein lipase was purified from bovine milk and labeled with 125I. After intravenous injection to rats the labeled lipase rapidly disappeared from the blood. The initial half-life was about 1 min and more than 70% of the radioactivity was found in the liver at 10 min. 30 min after the injection about 10% of the injected radioactivity was present in acid-soluble form in blood, indicating that the enzyme had been rapidly degraded. Injection of asialofetuin, ribonuclease B or mannan in amounts known to block the hepatic receptors for glycoproteins with exposed galactose, N-acetylglucosamine or mannose residues did not retard the removal of the lipoprotein lipase. Thus, some other, as yet undefined, receptor is implicated. Lipoprotein lipase is known to bind to heparin and some related polysacchrides. Heparin injected before the enzyme delayed its removal and heparin injected after the enzyme caused an immediate increase in blood radioactivity, signifying return from tissues to blood of labeled enzyme. Lipoprotein lipase is present at the endothelium in several extrahepatic tissues and is rapidly turned over. Its presence in blood in appreciable amounts would cause a derangement of lipid transport. The efficient hepatic removal of the enzyme may thus serve an important physiological purpose in keeping the blood levels of this enzyme low.
 ...
PMID:Rapid removal to the liver of intravenously injected lipoprotein lipase. 9 43

The bacteriocin produced by Mycobacterium smegmatis ATCC 14468 was isolated, and a study was made of its chemical, physical, and biological properties. No appreciable bacteriocin activity was found in the culture supernatant fluids, but it was released in appreciable quantities after disruption of the cells. The material was purified 49-fold by means of chromatography on diethylaminoethyl-cellulose, ammonium sulfate fractionation, gel filtration on Sephadex G-200, and chromatography on diethylaminoethyl-Sephadex A-50. Its molecular weight was determined to be approximately 75,000 from the elution profile on Sephadex G-200 chromatography. The bacteriocin was resistant to deoxyribonuclease, ribonuclease, lipase, ultraviolet irradiation, and freeze-thawing, whereas it was relatively less thermostable and was sensitive to proteolytic enzymes. The lethal effect of the bacteriocin was demonstrated by the decrease in viable counts of the bacteriocin-sensitive indicator strain, M. diernhoferi ATCC 19340. The bacteriocin preparation inhibited the growth of HeLa-S3 cells.
 ...
PMID:Purification, properties, and cytotoxic effect of a bacteriocin from Mycobacterium smegmatis. 46 82

A strain of Actinomyces odontolyticus, originally isolated from human dental plaque, produced a non-dialyzable, trypsin-sensitive substance that was bactericidal for certain strains of bifidobacteria at 42 degrees C but not at 37 degrees C. Detectable quantities of the bacteriocin were not produced in liquid media. Experimentally useful yields were obtained by extraction from pour plate cultures of producer cells. At 42 degrees C, exponential killing did not occur until indicator cells had doubled at least once. At 37 degrees C, the bacteriocin effected a transient bacteriostasis. Partially purified concentrates were obtained by diethylaminoethyl-cellulose chromatography, and such material was not inactivated by ribonuclease, deoxyribonuclease, or lipase. Pronase, trypsin, and exposure to 100 degrees C for 20 min completely abolished activity. Inhibitory activity was considerably reduced by exposure to a pH of either 3 or 11. Treatment of producer cells with curing agents did not induce a high frequency of non-bacteriocinogenic cells. The odontolyticin was adsorbed by susceptible, as well as resistant, bacteria.
 ...
PMID:Bacteriocin from Actinomyces odontolyticus with temperature-dependent killing properties. 90 31

The binding of taurodeoxycholate to pancreatic lipase and a few other proteins has been studied with equilibrium dialysis and in gel filtration experiments. A three compartment dialysis cell has been used; with this cell, complete equilibration is not necessary for calculation of the binding even at bile salt concentrations above the critical micellar concentration. The results indicate that taurodeoxycholate does not bind to lipase below the critical micellar concentration, that the binding starts in the critical micellar concentration range of the bile salt and reaches around 12 mol taurodeoxycholate per mol of lipase at taurodeoxycholate concentrations well above the critical micellar concentration. Previous results indicating a binding of maximally 1-2 mol taurodeoxycholate/mol lipase were too low, depending on the experimental conditions in which complete equilibration was not obtained. The binding isotherm for taurodeoxycholate to lipase is similar to that for co-lipase; colipase and lipase in mixture bind as much taurodeoxycholate as the sum for the single proteins. Taurodeoxycholate binds to ribonuclease and chymotrypsinogen to a similar extent as to lipase.
 ...
PMID:On the binding of bile salt to pancreatic lipase. 100 92

An in vitro system of guinea pig pancreatic lobules convenient for the study of secretory processes is described in this paper. In this system: (a) the over-all glandular architecture of the tissue is preserved: lobules remain morphologically intact through 5 hours; (b) amylase discharge from unstimulated lobules is low (similar to 4%/hour) and linear over the 5 hours tested; (c) response to carbamylcholine chloride (10-5 M) is energy-dependent, rapid, and extensive (92% discharge of amylase by 5 hours); (d) initial rates of discharge remain stable over the first 3 hours; and (e) no autoactivation of zymogens occurs in incubation medium or tissue. The activation of four zymogens, i.e. chymotrypsinogen, trypsinogen, and procarboxypeptidases A and B, was studied using the following criteria for optimal activation: (a) maximal activation attainable under experimental conditions; (b) stability at the level of maximal activation; and (c) linear relationship between amounts of protein activated and enzyme activity elicited by activation. The concentration of activators (trypsin or enterokinase) and secretory protein, the presence or agents (bovine plasma albumin or Triton X-100) which minimize adsorptive losses of secretory protein on glass or plastic surfaces, and the temperature at which activation is carried out were found to be critical and different for each of the zymogens tested. The kinetics of the appearance of three enzyme activities (amylase, lipase, and ribonuclease) and four potential proteolytic activities (chymotrypsinogen, trypsinogen, and procarboxypeptidases A and B) into the incubation medium was studied under different conditions; i.e. rest and stimulation with various secretogogues (carbamylcholine chloride, caerulein, and pancreozymin). All seven activities estimated to represent similar to 75% of the secretory protein output of the exocrine pancreas were discharged in synchrony and in constant proportions and were released from the tissue to the same extent under each experimental condition investigated.
 ...
PMID:Studies on the guinea pig pancreas. Parallel discharge of exocrine enzyme activities. 112 25

Strains from type culture collections and clinical isolates belonging to the Aeromonas and Pseudomonas genera were identified with conventional tests. Production of extra-cellular enzymes and haemolysins were detected by simple plate agar methods. The following enzymes were found to be of special value for a rapid and simple classification of certain species in both genera: potease (casein and gelatin agar), lecithinase (lecithin agar), and deoxyribonuclease (DNA agar). Elastase, staphylolytic enzyme, lipase, ribonuclease, amylase, and egg yolk reaction were other enzymes studied. However, these tests were not positive for more than 90% of any species. A. hydrophila, A. salmonicida, and P. aeruginosa were haemolytic on agar containing rabbit erythrocytes.
 ...
PMID:Characterization of three Aeromonas and nine pseudomonas species by extracellular enzymes and haemolysins. 117 Apr 82

A comparative enzyme analysis was performed on 3 pancreatic extracts generally used for dermal-epidermal separation, namely, crude trypsin (Difco), crude trypsin (Sigma) and pancreatin. A fourth pancreatic extract, crude lipase, was subjected to a corresponding analysis. The 4 extracts were assayed for activities of: protease (total), trypsin, chymotrypsin, carboxypeptidase-A, amylase, elastase, lipase, esterase, arylesterase and ribonuclease. Relative activities of the different proteolytic enzymes were individualized by utilizing specific inhibitors. Insignificant differences were observed between the enzyme activities of crude trypsin (Difco) and pancreatin. Crude lipase displayed similar enzyme activities as these two extracts in addition to high lipolytic, esterolytic and arylesterolytic activities. Crude trypsin (Sigma) exhibited higher tryptic and chymotryptic activities than the other extracts but lacked all further enzyme activities. Epidermal separation was performed using similar incubation conditions for each extract and skin from the same donor. Ultrastructural examination of the detached epidermis revealed that a more effective separation could be achieved by crude lipase.
 ...
PMID:An analysis of pancreatic enzymes used in epidermal separation. 123 61

Changes in the activities of three gastric and nine pancreatic enzymes plus colipase were determined during postnatal development and weaning in calves. In calves exclusively milk-fed for 2, 7, 28, 56, 70 and 119 d, the enzyme activities per kilogram of empty live weight increased with age for chymotrypsin, elastase, carboxypeptidases A and B, ribonuclease and alpha-amylase, decreased for chymosin, lysozyme and colipase but showed no change in the case of pepsin, trypsin, lipase and phospholipase A2 compared with animals at birth. The greatest increase was that in alpha-amylase activity (about 50-fold between d 2 and 119). In calves weaned between d 28 and 56, all the activities were higher than in milk-fed animals, except that of chymosin (which was slightly lower) and that of colipase (which did not change). At 119 d of age, chymotrypsin, carboxypeptidase A, alpha-amylase and lipase were 1.6- to fourfold higher in ruminants than in preruminants. Thus, most enzyme activities were modified first by colostrum and milk intake, and again upon weaning by development of the forestomachs and ingestion of solid food. These ontogenic patterns might be under the control of many gut regulatory peptides, the plasma concentrations of which changed simultaneously. Some gastric and pancreatic enzymes were correlated to plasma concentrations of these gut regulatory peptides.
 ...
PMID:Gastric and pancreatic enzyme activities and their relationship with some gut regulatory peptides during postnatal development and weaning in calves. 137 46

Rat pancreatic secretory proteins were separated by an automated liquid chromatography system utilizing a Mono S cation-exchange column. Optimal resolution was obtained with a multistep salt and pH gradient (0.01-2 M LiCl, pH 5.3-63). A total of fourteen well-separated peaks, as well as several minor peaks, were detected by UV absorption. The main pancreatic enzymes were resolved (two amylases, two chymotrypsinogens, two trypsinogens, proelastase, lipase, prophospholipase A2, procarboxypeptidase A, procarboxypeptidase B, and ribonuclease). In addition, proteins without enzymic activity, such as lithostathine and pancreatitis-associated protein, were identified. Activation of proenzymes did not occur during the separation. At a flow-rate of 0.5 ml/min, ca. 250 micrograms to 5 mg of protein could be applied with equal resolution. The reproducibility of retention volumes and peak areas was high (less than 1% or 5% variation, respectively). When radiolabeled proteins were separated, a comparable pattern of peaks was obtained. The technique described is, therefore, not only useful for analytical and preparative separation of pancreatic proteins but can additionally serve for quantitative determination of the pancreatic isoenzyme pattern.
 ...
PMID:Separation of rat pancreatic secretory proteins by cation-exchange fast protein liquid chromatography. 140 Jul 16

Intravenous infusion of synthetic secretin for periods up to 24 h in conscious rats was combined with in-vitro amino acid incorporation in isolated pancreatic lobules and high-resolution separation of individual enzyme proteins by two-dimensional isoelectric focusing and SDS gel electrophoresis. With this method persistent changes in the biosynthesis of ten enzyme and isoenzyme proteins can be studied as a result of prolonged secretin stimulation. Three major patterns of response were observed: progressive increases in the synthetic rates were found in six out of ten enzyme proteins with most pronounced changes in the synthetic rates of lipase (4.10-fold increase), two forms of proelastase (2.80-fold increase, respectively), the two acidic forms of trypsinogen and chymotrypsinogen (2.60- and 2.40-fold increase, respectively), and of ribonuclease (2.30-fold increase). Only moderate changes (1.30- to 1.90-fold increase) occurred in the synthetic rates of four isoenzymatic forms of procarboxypeptidase and the basic forms of chymotrypsinogen and trypsinogen, respectively. No absolute change in the rate of synthesis was observed in both forms of amylase. These data obtained after secretin stimulation differ significantly from previous results after caerulein stimulation, but it is not clear so far whether this is due to differential effects of the two second messengers released by each of the hormones on the level of transcription or translation.
 ...
PMID:In-vivo stimulation of rat pancreatic acinar cells by infusion of secretin. II. Changes in individual rates of enzyme and isoenzyme biosynthesis. 241 53


1 2 3 4 5 6 Next >>