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  • 1
    Electronic Resource
    Electronic Resource
    The localization and characterization of proteinases for the initial cleavage of porcine amelogenin (1992)
    Springer
    Calcified tissue international 51 (1992), S. 213-217 
    Details
    ISSN: 1432-0827
    Keywords: Porcine secretory enamel ; Degradation of amelogenin ; Proteinases ; 25kDa amelogenin ; Enzymography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In the outermost layer of porcine-developing enamel adjacent to the ameloblasts in the secretory stage, the activities of two proteinases having molecular masses of 76 and 78kDa were detected by enzymography using gelatin as a substrate. On the other hand, high activities of known 30 and 34kDa proteinases were localized in the inner layer of the enamel. The 76kDa proteinase cleaved the carboxylterminal peptide of porcine 25kDa amelogenin to convert it to 20kDa amelogenin. The 78kDa proteinase also acted on the 25kDa amelogenin similarly, but its activity was weak. The results indicate that the 25kDa amelogenin synthesized and secreted by ameloblasts is converted to 20kDa amelogenin by the action of proteinase localized in the outermost layer of the secretory enamel, and then further degraded by the proteinases in the inner layer of the enamel associated with the increase of mineralization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334549
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  • 2
    Electronic Resource
    Electronic Resource
    Chromatographically different type II collagens from human normal and osteoarthritic cartilage
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 67 (1975), S. 1575-1580 
    Details
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0006-291X(75)90206-5
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  • 3
    Electronic Resource
    Electronic Resource
    Maturation of collagenous tissue: Specific in vivo proteolytic cleavage of only α1(I) chains
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 71 (1976), S. 651-657 
    Details
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0006-291X(76)90837-8
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  • 4
    Electronic Resource
    Electronic Resource
    Action of metalloproteinases on porcine dentin mineralization (1994)
    Springer
    Calcified tissue international 55 (1994), S. 426-435 
    Details
    ISSN: 1432-0827
    Keywords: Dentin mineralization ; Enzymography ; Geatinases ; Proteoglycanases ; Protoglycans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Samples containing predentin and mineralized dentin involving the mineralized front (newly formed dentin) were prepared by scraping developing porcine teeth after odontoblastic cell debris had been removed from the predentin surfaces. An extract was obtained separately from the matrices of predentin and of the newly formed dentin with a 4 M guanidine solution before and after demineralization with acetic acid solution. Enzymography detected 56 and 61 kDa gelatinases and 25 kDa proteoglycanase as neutral metalloproteinases in both extracts and proved them to be in an active form. Approximately half of the 56 and 61 kDa gelaunases binds to collagen fibers in predentin matrix. Three high molecular weight proteoglycans (70–85 kDa, 130–180 kDa, and 290 kDa) were found in the predentin matrix, but not in the newly formed dentin. The proteoglycanases in predentin degraded 290 kDa proteoglycan, if incubated together with calcium (Ca) ions. The results of this investigation indicate that active proteoglycanases with existed in the predentin perform no substantial work in proteoglycan degradation because the Ca ions are masked in the predentin matrix by coexisting proteoglycans. When mineralization occurs, however, they can degrade the proteoglycan at the mineralization front because excess Ca ions may be supplied via odontoblastic processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298556
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  • 5
    Electronic Resource
    Electronic Resource
    Porcine amelogenins (1994)
    Springer
    Calcified tissue international 54 (1994), S. 69-75 
    Details
    ISSN: 1432-0827
    Keywords: Porcine secretory enamel ; Porcine amelogenin ; Plasma desorption mass spectometry ; Amino acid sequence ; CNBr cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Amelogenins were extracted from the thin outer layer of porcine secretory enamel and purified by gel filtration and reverse-phase HPLC. The results of amino acid sequencing of the purified porcine amelogenins indicated the presence of at least four prototype amelogenins translated from alternatively spliced transcripts. The results of mass spectroscopy of the CNBr-cleaved peptides derived from the 25kDa amelogenin indicated that porcine 25kDa amelogenin is neither phosphorylated nor glycosylated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316293
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  • 6
    Electronic Resource
    Electronic Resource
    Epitaxial overgrowth of apatite crystals on the thin-ribbon precursor at early stages of porcine enamel mineralization (1993)
    Springer
    Calcified tissue international 53 (1993), S. 249-256 
    Details
    ISSN: 1432-0827
    Keywords: Enamel ; Amelogenesis ; Crystal growth ; Calcium phosphates ; Biomineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The aim of the present work was to investigate changes in cross-sectional morphologies of enamel crystallites as a function of location in secretory porcine enamel. Enamel tissues were obtained from 5- to 6-month-old slaughtered piglets. For examination by electron microscopy, a portion of the secretory enamel was embedded in resin and ultrathin sections were prepared with a diamond knife. In parallel studies, compositional and structural changes of enamel mineral were assessed by chemical analysis and Fourier transform infrared (FTIR) spectroscopy. For this purpose, two consecutive layers of the outer secretory enamel, each approximately 30 μm thick, were separated from the labial side of permanent incisors. Using high-resolution electron microscopy, early events of enamel crystal growth were characterized as the epitaxial growth of small apatite units on the lateral surfaces of the initially precipitated thin ribbon. These apatite units had regular triangle or trapezoid cross-sections. After fusions of those isolated trapezoids on both lateral sides of the platy template, the resulting enamel crystallites had the well-documented flattened-hexagonal shapes in cross-sections. The initially precipitated thin plate was buried inside the overgrown apatite lamella and then retained as a central dark line. Similar morphological evidence for the epitaxial nucleation and overgrowth of carbonatoapatite on the platy template was obtainedin vitro. Chemical and FTIR analyses of the enamel layer samples showed that the characteristics of the youngest enamel mineral were distinct from those of enamel crystals found in older secretory enamel. The overall results support the concept that initial enamel mineralization comprises two events: the initial precipitation of thin ribbons and the subsequent epitaxial growth of apatite crystals on the two-dimensional octacalcium phosphate-like precursor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320910
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  • 7
    Electronic Resource
    Electronic Resource
    Enamelins in the newly formed bovine enamel (1993)
    Springer
    Calcified tissue international 53 (1993), S. 257-261 
    Details
    ISSN: 1432-0827
    Keywords: Bovine enamelin ; Amelogenin ; Newly formed enamel ; Western blot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The possibility of using the antisera raised in rabbits against the porcine 25 kDa amelogenin, 32 and 89 kDa enamelins, and the 13–17 kDa nonamelogenin for the differentiation and identification of the protein components in bovine immature enamel was examined. Although the immunoreactivities of these antisera against bovine enamel proteins were weaker than those against the porcine proteins, it was found that these antisera could differentiate and demonstrate immunohistochemically a characteristic distribution of three different kinds of enamel protein components in the bovine secretory stage enamel similar to those observed in the porcine immature enamel. Of the several high molecular weight proteins being reactive to the anti-porcine 32 and 89 kDa enamelin sera, the 130 kDa protein, having the highest molecular weight, was extracted and purified from the bovine enamel sample which was obtained by peeling approximately 30-μm thickness of the outermost layer of the secretory stage enamel. The amino acid composition of the 130 kDa protein was similar to the known bovine enamelins, and was rich in aspartic acid, glutamic acid, proline, and glycine. The results could suggest that the enamelins of lower molecular weight than this protein, which are found in the bovine secretory stage enamel, are derived from this precursor protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320911
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  • 8
    Electronic Resource
    Electronic Resource
    Immunochemical and immunohistochemical study of the 27- and 29-kDa calcium-binding proteins and related proteins in the porcine tooth germ (1997)
    Springer
    Histochemistry and cell biology 107 (1997), S. 485-494 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Our previous report identified 27- and 29-kDa calcium-binding proteins in porcine immature dental enamel. In this study we revealed that the N-terminal amino acid sequences of the two proteins were identical: LLANPXGXIPNLARGPAGRSRGPPG. The sequence matches a portion of the amino acid sequence of the porcine sheath protein, sheathlin. Porcine tooth germs were investigated immunochemically and immunohistochemically using specific antibodies raised against synthetic peptide that included residues 13–25 of this sequence. The affinity-purified antibodies reacted with several proteins extracted from newly formed immature enamel in immunochemical analyses, especially protein bands migrating at 62, 35–45, 29, and 27 kDa in SDS-polyacrylamide gels. The largest protein detected was a weak band near 70 kDa. In immunochemical analyses of proteins extracted from the inner (old) immature enamel, the antibody reacted faintly with the 27- and 29-kDa proteins. In immunohistochemical preparations, the Golgi apparatus and secretory granules of the secretory ameloblast, and the surface layer of immature enamel showed immunoreactivity. The immunoreactivity of immature enamel just beneath the secretory face of the Tomes’ process was intense. No immunoreactivity was found in the Golgi apparatus of the maturation ameloblast. These results suggest that the 70-kDa protein, whose degradation might be very fast, is the parent protein of the 27- and 29-kDa proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004180050136
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  • 9
    Electronic Resource
    Electronic Resource
    Immunochemical and immunohistochemical studies, using antisera against porcine 25 kDa amelogenin, 89 kDa enamelin and the 13–17 kDa nonamelogenins, on immature enamel of the pig and rat (1991)
    Springer
    Histochemistry and cell biology 96 (1991), S. 129-138 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Enamel proteins were extracted from the newly formed layer of immature porcine enamel, and the 25 kDa amelogenin, 89 kDa enamelin and 13–17 kDa nonamelogenins were purified. Specific antisera were raised against these proteins. Antibodies specific to the C-terminal region (residues 149–173) of the 25 kDa amelogenin were generated by absorption of the anti-25 kDa amelogenin serum with 20 kDa amelogenin, which contains residues 1–148 of the antigen. Immunoelectrotransfer blotting of the extracted porcine enamel proteins showed that the anti-25 kDa amelogenin serum recognized the 25 kDa and other low and high molecular weight amelogenins. The C-terminal specific anti-25 kDa amelogenin serum reacted only with amelogenins having molecular weights over 23 kDa. The anti-89 kDa enamelin serum recognized the 89 kDa enamelin and lower molecular weight proteins, but neither the amelogenins nor the 13–17 kDa nonamelogenins. The antiserum against the 13–17 kDa nonamelogenins showed no cross reactivity to the 89 kDa enamelin, but recognized higher molecular weight nonamelogenins. In immunohistochemical preparations of the porcine tooth germs, the 25 kDa amelogenin-like immunoreactivity over immature enamel decreased in a gradient from the enamel surface to the middle layer. In the inner layer immunoreactivity was concentrated over the prism sheaths. The C-terminal specific 25 kDa amelogenin-like immunoreactivity was intense at the outer layer of immature enamel and decreased sharply toward the middle layer. Prism sheaths were intensely stained by the antiserum to the 13–17 kDa nonamelogenins. The 89 kDa enamelin-like immunoreactivity over enamel prisms was intense at the outer layer and decreased toward the middle layer. Staining by the anti-89 kDa enamelin serum of prism sheaths was faint. In immature rat incisor enamel, the C-terminal specific 25 kDa amelogenin antiserum demonstrated a staining pattern similar to that in the immature enamel of the pig. Distinct 13–17 kDa nonamelogenin-like and 89 kDa enamelin-like immunoreactivities were found especially in the layer adjacent to the Tomes' process. We conclude that some enamel proteins are degraded soon after their secretion from the secretory ameloblast in the rat and the pig. The specific enamel proteins which reacted with the antiserum to the 13–17 kDa nonamelogenins seem to be involved with the formation of prism sheaths in immature porcine enamel, but not in rat incisor enamel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315983
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