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Nucleic Acids Research Sep 1981Two novel sequence-specific endonucleases have been isolated from Proteus vulgaris, ATCC 13315. PvuI recognizes the sequence: 5' C G A T decrease C G 3' 3' G C increase...
Two novel sequence-specific endonucleases have been isolated from Proteus vulgaris, ATCC 13315. PvuI recognizes the sequence: 5' C G A T decrease C G 3' 3' G C increase T A G C 5' and PvuII recognizes the sequence: 5' C A G decrease C T G 3' 3' G T C increase G A C 5' and cleave as indicated by the arrow (decrease). PvuI is an isoschizomer of XorII, RshI, and XniI. No enzyme with the specificity of PvuII has been described previously.
Topics: Animals; Base Sequence; DNA Restriction Enzymes; Deoxyribonucleases; Pancreas; Proteus vulgaris; Substrate Specificity
PubMed: 6272209
DOI: 10.1093/nar/9.18.4525 -
Journal of Colloid and Interface Science Aug 2020Lipid cubic phase formulations have gained recognition as potential controlled delivery systems for a range of active pharmaceutical and biological agents on account of...
Lipid cubic phase formulations have gained recognition as potential controlled delivery systems for a range of active pharmaceutical and biological agents on account of their desirable physiochemical properties and ability to encapsulate both hydrophobic and hydrophilic molecules. The most widely studied lipid cubic systems are those of the monoacylglycerol lipid family. These formulations are susceptible to lipolysis by a variety of enzymes, including lipases and esterases, which attack the ester bond present on the lipid chain bridging the oleic acid component to the glycerol backbone. The release of poorly soluble molecules residing in the lipid membrane portions of the phase is limited by the breakdown of the matrix; thus, presenting a potential means for further controlling and sustaining the release of therapeutic agents by targeting the matrix stability and its rate of degradation. The aims of the present study were twofold: to evaluate an approach to regulate the rate of degradation of lipid cubic phase drug delivery systems by targeting the enzyme interactions responsible for their demise; and to study the subsequent drug release profiles from bulk lipid cubic gels using model drugs of contrasting hydrophobicity. Here, hybrid materials consisting of cubic phases with monoacylglycerol lipids of different chain lengths formulated with a potent lipase inhibitor tetrahydrolipstatin were designed. Modulation of the release of a hydrophobic model pharmaceutical, a clofazimine salt, was obtained by exploiting the matrices' enzyme-driven digestion. A stable cubic phase is described, displaying controlled degradation with at least a 4-fold improvement compared to the blank systems shown in inhibitor-containing cubic systems. Sustained release of the model hydrophobic pharmaceutical was studied over 30 days to highlight the advantage of incorporating an inhibitor into the cubic network to achieve tunable lipid release systems. This is done without negatively affecting the structure of the matrix itself, as shown by comprehensive small-angle x-ray scattering experiments.
Topics: Animals; Drug Liberation; Enzyme Inhibitors; Hydrophobic and Hydrophilic Interactions; Lipase; Lipids; Molecular Structure; Orlistat; Pancreas; Swine
PubMed: 32278949
DOI: 10.1016/j.jcis.2020.04.015 -
Molecules (Basel, Switzerland) Mar 2013The versatile oligosaccharide biopolymers, chitin and chitosan, are typically produced using enzymatic processes. However, these processes are usually costly because...
The versatile oligosaccharide biopolymers, chitin and chitosan, are typically produced using enzymatic processes. However, these processes are usually costly because chitinases and chitosanases are available in limited quantities. Fortunately, a number of commercial enzymes can hydrolyze chitin and chitosan to produce long chain chitin or chitosan oligosaccharides. Here, a platform to screen for enzymes with chitinase and chitosanase activities using a single gel with glycol chitin or glycol chitosan as a substrate was applied. SDS-resistant chitinase and chitosanase activities were observed for pancreatin. Its chitotriosidase had an optimal hydrolysis pH of 4 in the substrate specificity assay. This activity was thermally unstable, but independent of 2-mercaptoethanol. This is the first time a chitotriosidase has been identified in the hog. This finding suggests that oligochitosaccharides can be mass-produced inexpensively using pancreatin.
Topics: Animals; Chitin; Chitosan; Hexosaminidases; Hydrogen-Ion Concentration; Hydrolysis; Pancreas; Pancreatin; Substrate Specificity; Swine
PubMed: 23459306
DOI: 10.3390/molecules18032978 -
The Journal of Biological Chemistry Apr 1975An 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...
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.
Topics: Animals; Carboxypeptidases; Chymotrypsinogen; Endopeptidases; Enzyme Precursors; Enzymes; Guinea Pigs; Kinetics; Microscopy, Electron; Pancreas; Protein Kinases; Time Factors; Trypsin; Trypsinogen
PubMed: 1123325
DOI: No ID Found -
The Biochemical Journal Sep 1991Distribution of manganese (Mn) and its binding to specific proteins were examined in rat pancreas. A MnCl2 solution was injected subcutaneously into Wistar rats daily at...
Distribution of manganese (Mn) and its binding to specific proteins were examined in rat pancreas. A MnCl2 solution was injected subcutaneously into Wistar rats daily at a single dose of 15 mg of Mn/kg body weight for 10 days and the animals were killed 1 day after the last injection. The concentration of Mn in the pancreas increased considerably from 1.4 +/- 0.2 (control) to 13.3 +/- 3.7 micrograms/g wet tissue by the repeated injection of Mn. The distribution of Mn in the soluble fraction of the pancreas (170,000 g supernatant) was determined on a gel-filtration column (Asahipak GST-520) using an h.p.l.c.-inductively coupled argon plasma atomic-emission spectrometry (i.c.p.) technique. The metal was eluted as a single peak in the high-molecular-mass protein fraction, where Mn had been observed as a small peak in the control profile, suggesting that the administered Mn was bound to the same Mn-binding component as that in the control. On the basis of enzymic and chemical characterization of the protein, it was identified as a zymogen of carboxypeptidase B (pro-carboxypeptidase B, pro-CPB). The elution profiles of the protein by h.p.l.c.-i.c.p. indicated that Mn and zinc (Zn) were bound to the zymogen with a molar ratio of 1:4 in normal rat pancreas. Mn bound to the zymogen was easily replaced by Zn in vitro, suggesting that Mn was bound to the Zn-binding site and that the binding affinity to Zn was higher than that to Mn. The present results indicate that pro-CPB is the primary Mn-binding protein in the pancreas of control and also Mn-administered rats.
Topics: Amino Acid Sequence; Animals; Carboxypeptidase B; Carboxypeptidases; Chromatography, High Pressure Liquid; Enzyme Precursors; Male; Manganese; Molecular Sequence Data; Pancreas; Protein Binding; Rats; Rats, Inbred Strains; Tissue Distribution
PubMed: 1898371
DOI: 10.1042/bj2780857 -
The Journal of Biological Chemistry Oct 1975Kidney beans, Phaseolus vulgaris, contain a proteinaceous inhibitor of alpha-amylase, which we have named phaseolamin. The inhibitor has been purified to homogeneity by...
Kidney beans, Phaseolus vulgaris, contain a proteinaceous inhibitor of alpha-amylase, which we have named phaseolamin. The inhibitor has been purified to homogeneity by conventional protein fractionation methods involving heat treatment, dialysis, and chromatography on DEAE-cellulose, Sephadex G-100, and CM-cellulose. Phaseolamin is specific for animal alpha-amylases, having no activity towards the corresponding plant, bacterial, and fungal enzymes, or any other hydrolytic enzyme tested. Optimal inhibitory activity is expressed during preincubation of enzyme and inhibitor at pH 5.5 and 37 degrees. Substrate prevents inhibition. Measurement of the stoichiometry on inhibition showed that a 1:1 complex of alpha-amylase and inhibitor is formed. Complex formation was demonstrated by chromatography on Sephadex G-100. The phaseolamin-amylase complex is dissociated at low pH values, apparently as a result of destruction of the enzyme; the complex cannot be dissociated by other conditions unfavorable for inhibition (low temperature or high pH). Phaseolamin inhibits hog pancreatic alpha-amylase in a noncompetitive manner.
Topics: Amylases; Animals; Hemagglutination Tests; Humans; Hydrogen-Ion Concentration; Kinetics; Molecular Weight; Pancreas; Plant Proteins; Plants; Species Specificity; Swine
PubMed: 240849
DOI: No ID Found -
Gut Sep 1990We investigated exocrine pancreatic function in a population of patients with Crohn's disease in order to correlate the pancreatic function with clinical and laboratory...
We investigated exocrine pancreatic function in a population of patients with Crohn's disease in order to correlate the pancreatic function with clinical and laboratory variables. A total of 143 patients affected by Crohn's disease and 115 control subjects were studied. All had a Lundh meal test. As a group patients with Crohn's disease had significantly decreased activity of both amylase (p less than 0.02) and lipase (p less than 0.001) in duodenal aspirates. In patients with Crohn's disease enzyme activities were not correlated to duration of disease or to extent or localisation of previous bowel resection. The lowest enzyme values were found in patients with the most extensive bowel involvement, and they were significantly lower (p less than 0.05) than in patients with disease confined to the terminal ileum. The differences between enzyme values in other subgroups of patients were not significant. For the patient group as a whole no correlation was found between disease activity and enzyme values, but for the most uniform group of patients, those with terminal ileitis, pancreatic function was significantly lower (p less than 0.05) in patients with moderate and severe disease compared with patients with mild disease. Thus at least two factors seem to be responsible for impaired pancreatic function in Crohn's disease: firstly disease activity and secondly localisation or extent of disease.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Amylases; Crohn Disease; Duodenum; Female; Humans; Lipase; Male; Middle Aged; Pancreas; Pancreatic Function Tests
PubMed: 1698692
DOI: 10.1136/gut.31.9.1076 -
Transplantation Dec 2007Efficient islet isolation represents a necessary requirement for successful islet transplantation as a treatment for type 1 diabetes. The choice of collagenase for...
BACKGROUND
Efficient islet isolation represents a necessary requirement for successful islet transplantation as a treatment for type 1 diabetes. The choice of collagenase for pancreas digestion is critical for the isolation outcome, and Liberase is the most widely used enzyme, although large intra-batched variability in activity and efficiency has been observed.
METHODS
The aim of this study was to characterize Liberase components and their relative role in pancreas digestion. Liberase batches were characterized by microelectrophoresis.
RESULTS
By means of microelectrophoresis, we identified three main proteins each with different prevalences between batches. Two proteins were found to correspond to class I (CI) and one to class II (CII) collagenase. In a series of 163 islet isolations, we observed that the CII correlated with islet yield (P<0.001) and digestion time (P<0.001); additionally, CI directly correlated with purity (P=0.028). Finally, when CII and one of the CI isoforms were >50 percentile, 15 of 36 preparations were transplanted, with 27 of 127 transplanted in the other cases (P=0.013).
CONCLUSION
These results represent an important step toward the characterization of enzymes, with the final aim of identifying key components for a standardized product.
Topics: Cell Separation; Collagenases; Humans; Islets of Langerhans; Islets of Langerhans Transplantation; Pancreas; Thermolysin
PubMed: 18165766
DOI: 10.1097/01.tp.0000295719.88525.60 -
European Journal of Biochemistry May 1982Transition of bovine ribonuclease A from its monomeric to a dimeric form changes the pattern of enzymic activity response to ionic strength [Sorrentino, S., Carsana, A.,...
Transition of bovine ribonuclease A from its monomeric to a dimeric form changes the pattern of enzymic activity response to ionic strength [Sorrentino, S., Carsana, A., Furia, A., Doskocil, J., and Libonati, M. (1980) Biochim. Biophys. Acta. 609, 40-52]. To see whether this phenomenon could be common to other enzyme-substrate systems, the action of various dimeric and monomeric enzymes (ox pancreas deoxyribonuclease, hog spleen acid deoxyribonuclease, bovine seminal ribonuclease, egg-white lysozyme, and papain) on polyelectrolytic substrates has been studied under different conditions of ionic strength. Dimerization of ox pancreas deoxyribonuclease, lysozyme and papain was obtained by cross-linkage with dimethyl suberimidate. The main results of the investigation, similar to those obtained with ribonuclease A, are the following. 1. Enzyme monomers and dimers show markedly different patterns of activity response to ionic strength at given pH values: the reactions catalyzed by monomeric enzymes are highly modulated by salt, whereas those catalyzed by dimeric enzymes are not. In particular, at the reaction optimum the monomeric form of an enzyme is significantly more active than the dimeric one. 2. The optimum of the reaction catalyzed by a dimeric enzyme is shifted to higher ionic strengths in comparison with that of the reaction catalyzed by a monomeric enzyme. A model is proposed that could explain these results on the basis of the influence of ionic strength on the intramolecular dynamics of the enzyme molecule and its non-specific interactions with polyelectrolytic substrates.
Topics: Animals; Cattle; Deoxyribonuclease I; Deoxyribonucleases; Egg White; Endonucleases; Hydrogen-Ion Concentration; Male; Muramidase; Osmolar Concentration; Pancreas; Papain; Ribonucleases; Semen; Spleen; Substrate Specificity; Swine
PubMed: 6282587
DOI: 10.1111/j.1432-1033.1982.tb05923.x -
The Biochemical Journal Nov 1996The kinetic theory of substrate reaction during the modification of enzyme activity [Duggleby (1986) J. Theor. Biol. 123, 67-80; Wang and Tsou (1990) J. Theor. Biol....
The kinetic theory of substrate reaction during the modification of enzyme activity [Duggleby (1986) J. Theor. Biol. 123, 67-80; Wang and Tsou (1990) J. Theor. Biol. 142, 531-549] has been applied to a study of the inactivation kinetics of ribonuclease A by bromopyruvic acid. The results show that irreversible inhibition belongs to a non-competitive complexing type inhibition. On the basis of the kinetic equation of substrate reaction in the presence of the inhibitor, all microscopic kinetic constants for the free enzyme, the enzyme-substrate complex and the enzyme-product complex have been determined. The non-competitive inhibition type indicates that neither the substrate nor the product affects the binding of bromopyruvic acid to the enzyme and that the ionization state of His-119 may be the same in both the enzyme-substrate and the enzyme-product complexes.
Topics: Animals; Cattle; Enzyme Inhibitors; Kinetics; Models, Chemical; Pancreas; Pyruvates; Ribonuclease, Pancreatic; Substrate Specificity
PubMed: 8947485
DOI: 10.1042/bj3200187