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)

Human tooth slabs were used to observe the effect of several kinds of organic acids and proteolytic enzymes on the production of artificial caries of enamel. Acidic gels were made by formic, acetic and lactic acids separately or in mixed form. The experiments were done in a period of 10 days. After this the specimens were prepared in ground sections and observed under optic microscope. The depth of the artificial lesions was measured by a micrometric scale in the eye lens of the microscope. The enzymes used for investigation were papain, trypsin and collagenase. The surfaces of the tooth were treated with fresh enzyme solutions every day and then with mixed acid gels. This was done alternately every day in a period of ten days. The results showed that lesions produced by formic acid gel were deeper than those produced by other acids or mixed acid gels. No effect was observed on the depth of the lesion by enzymatic treatments.
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PMID:[The effect of several acids and proteolytic enzymes on the production of artificial caries]. 209 67

The paired helical filaments (PHFs) of Alzheimer's disease were purified by a strategy in which the neurons and amyloid plaque cores of protein (APCP) were initially isolated. This was achieved by several steps of isocratic sucrose centrifugations of increasing molarity and a discontinuous isotonic Percoll density gradient. After collagenase elimination of contaminating blood vessels, lysis of neurons was produced by SDS treatment. The released PHF cytoskeletons were separated from contaminating APCP and lipofuscin by sucrose density gradient. A final step consisted in the chemical purification of highly enriched PHFs and APCP components via a formic acid to guanidine hydrochloride transition. PHFs and APCPs were fractionated by size exclusion HPLC and further characterized and quantitated by automatic amino acid analysis. We also present some of the morphological and immunochemical characteristics of PHF polypeptides and APCP. Our studies indicate that apart from differences in localization and morphology, PHF and APCP significantly differ in (a) chemical structure (peptide and amino acid composition); (b) epitope specificity (antiubiquitin, antitau, antineurofilament); (c) physicochemical properties (structural conformation in guanidine hydrochloride); and (d) thioflavine T fluorescence emission. These parameters strongly suggest important differences in the composition and, probably, in the etiopathology of PHF and APCP of Alzheimer's disease.
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PMID:Isolation and chemical characterization of Alzheimer's disease paired helical filament cytoskeletons: differentiation from amyloid plaque core protein. 306 Apr 72

Normal adult rabbit corneas were digested with 5% pepsin and their collagens extracted with acetic acid. Collagen extracts were fractionated by differential salt precipitation. The 2.5 M NaCl fraction was then redissolved with tris buffer and precipitated with sodium acetate. The precipitate contained a high-molecular-weight disulfide-bonded aggregate which, upon reduction with mercaptoethanol, was converted into three distinct polypeptides having molecular weights between 45 and 66 Kd. These physical characteristics, together with the susceptibility of these polypeptides to collagenase and their amino acid composition, identified the high molecular weight aggregate as type VI collagen. Corneas from neonate rabbits and adult corneas containing 2-week-old scars were organ cultured in the presence of [14C] glycine to incorporate radiolabel into collagen. Tissues were digested with 0.02% pepsin and their collagens extracted with formic acid. The total radioactivity of the extracts and tissue residues was determined before the collagens were separated by SDS-polyacrylamide slab gel electrophoresis. Radioactive collagen polypeptides bands were then stained with Coomassie blue, processed for fluorography, and analyzed by densitometry. The results show that: (1) type VI collagen is synthesized by neonate corneas and healing adult corneas; (2) it is not readily solubilized from either corneal tissue by 0.02% pepsin digestion and formic acid extraction; and (3) the proportion of type VI collagen deposited in scar tissue is markedly lower than that found in neonate corneas.
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PMID:Heterogeneity of collagens in rabbit cornea: type VI collagen. 313 Mar 20

Deposition of amyloid in pancreatic islets is a common feature in human type 2 diabetic subjects but because of its insolubility and low tissue concentrations, the structure of its monomer has not been determined. We describe a peptide, of calculated molecular mass 3905 Da, that was a major protein component of amyloid-rich pancreatic extracts of three type 2 diabetic patients. After collagenase treatment, an extract containing 20-50% amyloid was solubilized by sonication into 70% formic acid and the peptide was purified by gel filtration followed by reverse-phase high-performance liquid chromatography. We term this peptide diabetes-associated peptide, as it was not detected in extracts of pancreas from any of six normal subjects. Diabetes-associated peptide contains 37 amino acids and is 46% identical to the sequences of rat and human calcitonin gene-related peptide, indicating that these peptides are related in evolution. Sequence identities with conserved residues of the insulin A chain were also seen in a 16-residue segment. On extraction, the islet amyloid is particulate and insoluble like the core particles of Alzheimer disease. Their monomers have similar molecular masses, each having a hydropathic region that can probably form beta-pleated sheets. The accumulation of amyloid, including diabetes-associated peptide, in islets may impair islet function in type 2 diabetes mellitus.
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PMID:Purification and characterization of a peptide from amyloid-rich pancreases of type 2 diabetic patients. 331 17

The effect of various concentrations of fluoride (F-) on cell proliferation, matrix formation and mineralization was examined in hamster molar tooth germs in premineralizing and mineralizing stages. The exposure lasted 16 h (mineralizing stages) and 24 h (premineralizing stages) and the F- levels ranged from 2.63 microM to 2.63 mM; [3H]-thymidine, [3H]-proline, 45Ca and 32PO4 were used as markers for cell proliferation, matrix formation and mineralization, respectively. The proline-labelled amelogenins were isolated by sequential extraction with water and formic acid and their nature examined by SDS-urea-polyacrylamide electrophoresis. Digestion by collagenase was used to assess the amount of proline incorporated into collagens. F- in concentrations up to 1.31 mM inhibited neither biosynthesis of DNA and amelogenins, nor synthesis of collagens and their hydroxylation. Amelogenins extracted from F- induced, non-mineralizing enamel matrix had the same electrophoretic mobility and the same degree of phosphorylation as amelogenins from normal, mineralizing enamel. However, F- increased the uptake of 45Ca and TCA-soluble 32P dose-dependently, starting with 52 microM. Thus, interference with secretion of enamel matrix by F- takes place at much lower concentrations than required to inhibit biosynthesis of enamel matrix.
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PMID:Short-term effects of fluoride on biosynthesis of enamel-matrix proteins and dentine collagens and on mineralization during hamster tooth-germ development in organ culture. 385 37

Second maxillary molars of hamsters were cultured in the presence or absence of 250 micrograms/ml vitamin C for periods up to 12 days. At various days, cultured explants were studied with histological and biochemical methods to investigate effects of vitamin C-deficiency on matrix production and mineralization in vitro. As biochemical parameters for protein synthesis and mineralization, uptake and incorporation of [3H]-proline, 45Ca and 32PO4 were used. To discriminate between synthesis of collagenous and non-collagenous proteins digestion of the [3H]-proline-labelled material by purified collagenase and its degree of hydroxylation were measured. Histologically, in control explants cultured with vitamin C, normal dentinogenesis, amelogenesis and mineralization in vitro were observed. In the vitamin C-deficient explants, odontoblasts produced an abnormal predentine matrix and de-differentiated. Eventually, this matrix mineralized aspecifically. In the presence of this abnormal matrix, ameloblasts failed to differentiate, which suggests that a cell-matrix type of interaction is involved in the differentiation of the pre-ameloblasts. Biochemically, in the vitamin C-deficient explants protein synthesis and collagen synthesis were reduced by about the same extent; the in-vitro produced collagens appeared under-hydroxylated and could, in degraded form, easily be extracted in formic acid. An increase of [3H]-proline solubility in formic acid in the control explants, however, paralleled enamel matrix production and was attributed to the solubilization of proline-rich enamel matrix proteins. The production of acid insoluble phosphate was not affected by vitamin C-deficiency. The uptakes of 45Ca and 32PO4 were retarded and the molar Ca:PO4 uptake ratio was lower, reflecting the histologically observed aspecific mineralization.
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PMID:A histological and biochemical study of the effect of vitamin C-deficiency on induction of amelogenesis in hamster molars in vitro. 631 49

A three step extraction procedure was carried out on intact hamster molar tooth germs in vitro labelled with 32PO4 and/or 3H-proline, in order to quantify separately the synthesis of dentine matrix (collagen) and the proline rich enamel matrix proteins. The extraction was based on the high solubility of the proline rich enamel matrix proteins compared with the relatively insoluble dentine matrix collagens. Pretreatment with 10% trichloroacetic acid (step 1) demineralized and removed the non-incorporated amino acids and/or small sized peptides. A consecutive water extraction (step 2) removed a large percentage of the phosphorylated amelogenins as assessed by SDS-urea-polyacrylamide-electrophoresis and amino acid analyses. Collagenase digestibility data showed that only small amounts of collagens were present in this extract. Further extraction with 10% formic acid (step 3) released only small amounts of amelogenins from the explants but also increased contamination with collagens and another predominantly low molecular components. Most of the 3H-activity remaining in the residues was found in the collagenase labile material and was considered to be an appropriate measure for production of dentine collagens. On the other hand, the residues also contained small amounts of 3H-labelled material with the same electrophoretic mobility as amelogenins but had much more 32P-activity than the amelogenins derived from the water and formic acid extracts. It is suggested that this material in the residues probably contains the crystal bound enamel matrix proteins.
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PMID:Biosynthesis of tooth germ proteins in vitro: a fast quantitative extraction of amelogenins from intact hamster molar tooth germs. 659 32

Reinvestigation of the chemical structure of beta-amyloid peptide (A beta) deposits in the vascular tissue of Alzheimer disease brains revealed that the 42-residue form A beta-(1-42), rather than the more soluble A beta-(1-40) form, is the predominant peptide. Following removal of the surrounding tissue with SDS and collagenase, A beta was solubilized in formic acid and purified by Superose 12 chromatography. Peptides generated by enzymatic and chemical digestion of the A beta were purified by HPLC and characterized by amino acid analysis, sequence analysis, and mass spectrometry. In the leptomeningeal vessels, the average ratio of A beta-(1-42)/A beta-(1-40) was 58:42, whereas in the parenchymal vessels this ratio was 75:25. Interestingly, vascular A beta contains considerably less isomerized and racemized aspartyl residues than does neuritic plaque A beta, suggesting that the vascular amyloid is "younger." The discrete nature of the bands and spherical deposits of A beta associated with arterioles and capillaries, respectively, suggests that this amyloid arises from the vascular tissue itself. Increasing A beta deposition appears to lead to the distortion and occlusion of capillaries, which may contribute significantly to the pathology of Alzheimer disease.
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PMID:beta-Amyloid-(1-42) is a major component of cerebrovascular amyloid deposits: implications for the pathology of Alzheimer disease. 824 78

The use of collagen as a biomedical implant raises safety issues with regard to viruses and prions. Specific chemical agents that inactivate prion infectivity could be applied to collagen implants. The physicochemical changes and the in vitro and in vivo biocompatibility of collagen treated by formic acid (FA), trifluoroacetic acid (TFA), tetrafluorethanol (TFE), and hexafluoroisopropanol (HFIP) were investigated. In addition, the effects of these treatments on nucleic acids incorporated in collagen were analyzed. The molecules of FA and, more important, of TFA remained within collagen. FA, TFA, and HFIP treatments modify the secondary structure of collagen, as shown by Fourier transform infrared spectroscopy, while TFE does not. Differential scanning calorimetry measurements showed a decrease in the denaturation temperature compared to untreated collagen. However, resistance to collagenase was modified only after HFIP treatment. In vitro, cell growth was not impaired; in vivo, implants induced a temporary inflammatory reaction that was prolonged with TFA and HFIP treatments. TFE and FA-treated collagen were thoroughly infiltrated by fibroblasts. On the other hand, FA and TFA resulted in extensive depurination of nucleic acids while HFIP and TFE did so to a lesser degree. Among the investigated chemical scrapie inactivators, FA treatment could offer a safe and biocompatible collagen-derived material for biomedical use.
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PMID:Chemical inactivators as sterilization agents for bovine collagen materials. 935 14