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Alina Sionkowska - One of the best experts on this subject based on the ideXlab platform.
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thermal denatuRation of uv irradiated wet Rat Tail Tendon collagen
International Journal of Biological Macromolecules, 2005Co-Authors: Alina SionkowskaAbstract:The thermal helix-coil transition of UV irradiated collagen in Rat Tail Tendon has been investigated by differential scanning calorimetry. During UVB irradiation the Tendons were immersed in water to keep the collagen fibers in a fully hydRated condition at all times. UV irradiation induced changes in collagen which caused both stabilization and destabilization of the triple helix in fibers. The helix-coil transition for non-irradiated collagen occurred near 64 degrees C, for irradiated 1 and 3 h at 66 and 67 degrees C, respectively. After irradiating for longer times (20-66 h) the helix-coil transition peak occurred at much lower tempeRatures. The peak was very broad and suggested that collagen was reduced by UV to different polypeptides of different molecular weight and different lower thermal stabilities. It was caused by the disruption of a network of hydrogen-bonded water molecules surrounding the collagen macromolecule.
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thermal denatuRation of uv irradiated wet Rat Tail Tendon collagen
International Journal of Biological Macromolecules, 2005Co-Authors: Alina SionkowskaAbstract:Abstract The thermal helix-coil transition of UV irradiated collagen in Rat Tail Tendon has been investigated by differential scanning calorimetry. During UVB irradiation the Tendons were immersed in water to keep the collagen fibers in a fully hydRated condition at all times. UV irradiation induced changes in collagen which caused both stabilization and destabilization of the triple helix in fibers. The helix-coil transition for non-irradiated collagen occurred near 64 °C, for irradiated 1 and 3 h at 66 and 67 °C, respectively. After irradiating for longer times (20–66 h) the helix-coil transition peak occurred at much lower tempeRatures. The peak was very broad and suggested that collagen was reduced by UV to different polypeptides of different molecular weight and different lower thermal stabilities. It was caused by the disruption of a network of hydrogen-bonded water molecules surrounding the collagen macromolecule.
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mechanical properties of uv irradiated Rat Tail Tendon rtt collagen
International Journal of Biological Macromolecules, 2004Co-Authors: Alina Sionkowska, T. J. WessAbstract:Abstract The mechanical properties of RTT collagen Tendon before and after UV irradiation have been investigated by mechanical testing (Instron). Air-dried Tendon were submitted to treatment with UV irradiation (wavelength 254 nm) for different time intervals. The changes in such mechanical properties as breaking strength and percentage elongation have been investigated. The results have shown, that the mechanical properties of the Tendon were greatly affected by time of UV irradiation. Ultimate tensile strength and ultimate percentage elongation decreased after UV irradiation of the Tendon. Increasing UV irradiation leads to a decrease in Young’s modulus of the Tendon.
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thermal helix coil transition in uv irradiated collagen from Rat Tail Tendon
International Journal of Biological Macromolecules, 1999Co-Authors: Alina Sionkowska, Anna KaminskaAbstract:Abstract The thermal helix-coil transition in UV irradiated collagen solution, collagen film and pieces of Rat Tail Tendon (RTT) were compared. Their thermal stability’s were determined by differential scanning calorimeter (DSC) and by viscometric measurements. The denatuRation tempeRatures of collagen solution, film and pieces of RTT were different. The helix-coil transition occur near 40°C in collagen solution, near 112°C in collagen film, and near 101°C in pieces of RTT. After UV irradiation the thermal helix-coil transition of collagen samples were changed. These changes depend on the degree of hydRatation.
Thirumalachari Ramasami - One of the best experts on this subject based on the ideXlab platform.
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effect of hydrogen bond breaking reagent urea on the dimensional stability of Rat Tail Tendon rtt collagen fiber
Journal of Applied Polymer Science, 2002Co-Authors: R Usha, Thirumalachari RamasamiAbstract:Influence of hydrogen-bond-breaking reagents such as urea on shrinkage tempeRature, isometric tension, swelling behavior, tensile strength, and percentage extension of native Rat Tail Tendon (RTT) were examined. The swelling behavior was observed with polarizing optical microscopy and scanning electron microscopy. The results show that the lyotropic swelling increased the width of the fiber and was associated with the action of urea on the collagen fiber. HydRation properties led to significant variations in the swelling phenomenon. Lyotropic swelling produced opaque, limp, and flaccid fibers that did not change appreciably in length. The melting behavior and the swollen fascicles were clearly seen in scanning electron micrographs of 3 and 6M urea-treated RTT. The reduction in the dimensional stability of native RTT collagen fiber on treatment with urea demonstRated the role of secondary structure in the dimensional stabilization of collagen. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 975–982, 2002; DOI 10.1002/app.10262
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role of secondary structure on the stress relaxation processes in Rat Tail Tendon rtt collagen fibre
Macromolecular Bioscience, 2001Co-Authors: R Usha, V. Subramanian, Thirumalachari RamasamiAbstract:One of the important physical properties of collagen is viscoelasticity. The molecular and the matrix stability of collagen arises from the interplay of wide range of forces, namely covalent and hydrogen bonding, ionic interactions, hydrophobic interactions, van der Waals forces and weak interactions. Therefore, the stress relaxation behaviour of native Rat Tail Tendon (RTT) collagen fibre has been studied in water, saline media, 1, 3 and 6 M urea solutions, 0.02 M tris(maleate) buffer at pH 4–8 and 7 mol-% of methanol, ethanol and propanol at various tempeRatures. Experimental values of fractional stress change σ/σ0 as a function of time have been fitted to one-, two- and three-term models. The results show that the two-term model is the best fit for the experimental data. Two different Rates of relaxation (fast and slow) have been computed using a non-linear least-squares fit. Arrhenius plots of the tempeRature dependence of the Rates constant are non-linear. The activation energy values at absolute zero have been computed using the Rates of relaxation under different experimental conditions. Thermodynamic parameters have also been calculated using the Rates of relaxation.
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effect of crosslinking agents basic chromium sulfate and formaldehyde on the thermal and thermomechanical stability of Rat Tail Tendon collagen fibre
Thermochimica Acta, 2000Co-Authors: R Usha, Thirumalachari RamasamiAbstract:The role of covalent and coordinate covalent crosslinks on the thermal and mechanical properties of Rat Tail Tendon (RTT) collagen fibre has been studied. The Tendons were tanned with formaldehyde (HCHO) and basic chromium sulfate (BCS). Thermal properties of the crosslinked fibres were studied using shrinkage tempeRature, hydrothermal isometric tension behaviour and differential scanning calorimetry (DSC). Mechanical properties were analysed using tensile strength and stress relaxation behaviour. The results show that BCS tanned RTT exhibits a marked increase in the peak tempeRature and enthalpy changes when compared to both native and HCHO tanned RTT. This may be due to a net increase in the number of intermolecular crosslinks arising from both electrovalent and coordinate covalent interactions during BCS tanning. After treatment with urea there is a decrease in the peak tempeRature and the enthalpy changes of BCS tanned RTT fibres suggesting alteRations in the secondary structure of collagen are possible even after tanning. An increased long range order is seen in the case of chromium tanned fibres in comparison to HCHO treated analogue.
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effect of ph on dimensional stability of Rat Tail Tendon collagen fiber
Journal of Applied Polymer Science, 2000Co-Authors: R Usha, Thirumalachari RamasamiAbstract:The organized molecular structure of collagen is related to its dimensional stability. The dimensional stability of collagen arises from the interplay of various intermolecular forces such as covalent, hydrogen bonding, electrostatic interactions, hydrophobic interactions, London or van der Waals forces, and weak interactions. A structure–function relationship exists in collagen. Electrostatic interactions play an important role in dimensional stabilization. The dimensional stability of Rat Tail Tendon (RTT) collagen fiber is affected by the change in the net fixed charge on the molecule as a function of pH. Thermal and mechanical properties are dependent on molecular and lattice orders. The pH dependence of thermal shrinkage, isometric tension, differential scanning calorimetry, swelling behavior, tensile strength, and percent extension and stress relaxation behavior are studied in 0.02M Tris-maleate buffer at pH 4–8. The observed experimental results provide compelling evidence that electrostatic interactions play an important role in the dimensional stability of RTT collagen. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1577–1584, 2000
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influence of hydrogen bond hydrophobic and electrovalent salt linkages on the transition tempeRature enthalpy and activation energy in Rat Tail Tendon rtt collagen fibre
Thermochimica Acta, 1999Co-Authors: R Usha, Thirumalachari RamasamiAbstract:Abstract The influence of hydrogen bonding, hydrophobic and electrostatic interactions on the thermal stability of Rat Tail Tendon collagen fibre has been studied using differential scanning calorimetry (DSC) and hydrothermal isometric tension (HIT) experiments. The reagents used to study these effects are urea (hydrogen bonding), aqueous alcohols (hydrophobic) and 0.02 M Tris-maleate buffer at pH 4–8 (electrostatic interactions). The peak tempeRature, enthalpy changes and energy of activation for collagen to gelatin transition are computed using DSC. The peak tempeRature and enthalpy changes decrease with increasing concentRations of urea, increasing chain length of alcohol and decreasing pH. The shape of the isometric tension curves of the collagen fibres provide information on the crosslinking of collagen fibre while the extent of relaxation after maximum tension is indicative of thermally stable crosslinks.
Andrew D Cronshaw - One of the best experts on this subject based on the ideXlab platform.
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peptide sequences in glutaraldehyde linked proteodermatan sulphate collagen fragments from Rat Tail Tendon locate the proteoglycan binding sites
Biochemical Society Transactions, 1997Co-Authors: John E Scott, Mark Ritchie, Robert W Glanville, Andrew D CronshawAbstract:Collagen fibrils associate noncovalently with proteodmman sulphates (PDSs) at specitic and regular sites in the gap zone, at the d or e band. We call these strudures 'shape modules' because they appear to organise the collagen fibril matrix [l]. A shape module is a quaternary structure, collagen fibril4DS protein core+ AGAG chaiwAGAG chairwPDS protein coreccollagen fibril. Inspection of collagen fibril aminoacid sequences in PDS binding regions implicated 1 l-residue stretches in a1 chains [2] vvhich marry wll to the structure of PDS in complementary binding sites [3]. Alternative wggastions [4] rely on much less specific data, especially in vitm models [5] that are capable of several interpetations [6]. The most relevant and valid approach is to investigate the tissue directly. Our aim WBS to prepare a fragment of collegen from tissue with PDS covalently attached that could be sequenced to determine the composition and position of this binding site within the collagen molecule. We used glutaraldehyde as the crosslinker since this fixes the proteoglycans at their specific binding sites [7]. Freeze dried Rat Tail Tendon (RlT) was fixed in 0.2% glutaraldehyde solution at pH 6.5, reduced with 0.1M sodium borohydride, extracted with 2M MgC12 at 1OOOC and then digested with type VII clostridial collagenase at pH 7.4. The supernatant was precipitated with cetylpyridiniurn chloride (CPC) to recover PDS-rich species. Hydroxyproline and polyanion analyses, electrophoreses with Alcian blue [8] or Coomassie blue staining wre performed on deposits and extracts, before and after papain digestion. Aminoacid analyses and Edman sequencing w r e carried out on the PDS rich fractions. Controls were based on unfixed RlT. Fixed RTT remained >95% intact after hot MgC12 extraction compared with 40% of unfixed RTT. Over 90 % of the hydroxyproline from extracted fixed RTT was solubilised by collagenase digestion, the CPC product containing both polyanion and hydroxyproline. Edman sequencing of the CPC product revealed Gly as the only significant N terminal residue and further showed a sequence GAKGDRGET in a complex mixture which is characteristic of the a1 chain in the e band in the quarter stassered array. This finding is compatible with the model (31 in which PDS is associated at around residues 855-865 in the a1 chain. It is also compatible with one of four possible binding sites that are otherwise not convincingly differentiable, derived from in vitm models [5].
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135 peptide sequences in glutaraldehyde linked proteodermatan sulphate collagen fragments from Rat Tail Tendon locate the proteoglycan binding sites
Biochemical Society Transactions, 1997Co-Authors: John E Scott, Mark Ritchie, Robert W Glanville, Andrew D CronshawAbstract:Collagen fibrils associate noncovalently with proteodmman sulphates (PDSs) at specitic and regular sites in the gap zone, at the d or e band. We call these strudures 'shape modules' because they appear to organise the collagen fibril matrix [l]. A shape module is a quaternary structure, collagen fibril4DS protein core+ AGAG chaiwAGAG chairwPDS protein coreccollagen fibril. Inspection of collagen fibril aminoacid sequences in PDS binding regions implicated 1 l-residue stretches in a1 chains [2] vvhich marry wll to the structure of PDS in complementary binding sites [3]. Alternative wggastions [4] rely on much less specific data, especially in vitm models [5] that are capable of several interpetations [6]. The most relevant and valid approach is to investigate the tissue directly. Our aim WBS to prepare a fragment of collegen from tissue with PDS covalently attached that could be sequenced to determine the composition and position of this binding site within the collagen molecule. We used glutaraldehyde as the crosslinker since this fixes the proteoglycans at their specific binding sites [7]. Freeze dried Rat Tail Tendon (RlT) was fixed in 0.2% glutaraldehyde solution at pH 6.5, reduced with 0.1M sodium borohydride, extracted with 2M MgC12 at 1OOOC and then digested with type VII clostridial collagenase at pH 7.4. The supernatant was precipitated with cetylpyridiniurn chloride (CPC) to recover PDS-rich species. Hydroxyproline and polyanion analyses, electrophoreses with Alcian blue [8] or Coomassie blue staining wre performed on deposits and extracts, before and after papain digestion. Aminoacid analyses and Edman sequencing w r e carried out on the PDS rich fractions. Controls were based on unfixed RlT. Fixed RTT remained >95% intact after hot MgC12 extraction compared with 40% of unfixed RTT. Over 90 % of the hydroxyproline from extracted fixed RTT was solubilised by collagenase digestion, the CPC product containing both polyanion and hydroxyproline. Edman sequencing of the CPC product revealed Gly as the only significant N terminal residue and further showed a sequence GAKGDRGET in a complex mixture which is characteristic of the a1 chain in the e band in the quarter stassered array. This finding is compatible with the model (31 in which PDS is associated at around residues 855-865 in the a1 chain. It is also compatible with one of four possible binding sites that are otherwise not convincingly differentiable, derived from in vitm models [5].
R Usha - One of the best experts on this subject based on the ideXlab platform.
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effect of hydrogen bond breaking reagent urea on the dimensional stability of Rat Tail Tendon rtt collagen fiber
Journal of Applied Polymer Science, 2002Co-Authors: R Usha, Thirumalachari RamasamiAbstract:Influence of hydrogen-bond-breaking reagents such as urea on shrinkage tempeRature, isometric tension, swelling behavior, tensile strength, and percentage extension of native Rat Tail Tendon (RTT) were examined. The swelling behavior was observed with polarizing optical microscopy and scanning electron microscopy. The results show that the lyotropic swelling increased the width of the fiber and was associated with the action of urea on the collagen fiber. HydRation properties led to significant variations in the swelling phenomenon. Lyotropic swelling produced opaque, limp, and flaccid fibers that did not change appreciably in length. The melting behavior and the swollen fascicles were clearly seen in scanning electron micrographs of 3 and 6M urea-treated RTT. The reduction in the dimensional stability of native RTT collagen fiber on treatment with urea demonstRated the role of secondary structure in the dimensional stabilization of collagen. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 975–982, 2002; DOI 10.1002/app.10262
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role of secondary structure on the stress relaxation processes in Rat Tail Tendon rtt collagen fibre
Macromolecular Bioscience, 2001Co-Authors: R Usha, V. Subramanian, Thirumalachari RamasamiAbstract:One of the important physical properties of collagen is viscoelasticity. The molecular and the matrix stability of collagen arises from the interplay of wide range of forces, namely covalent and hydrogen bonding, ionic interactions, hydrophobic interactions, van der Waals forces and weak interactions. Therefore, the stress relaxation behaviour of native Rat Tail Tendon (RTT) collagen fibre has been studied in water, saline media, 1, 3 and 6 M urea solutions, 0.02 M tris(maleate) buffer at pH 4–8 and 7 mol-% of methanol, ethanol and propanol at various tempeRatures. Experimental values of fractional stress change σ/σ0 as a function of time have been fitted to one-, two- and three-term models. The results show that the two-term model is the best fit for the experimental data. Two different Rates of relaxation (fast and slow) have been computed using a non-linear least-squares fit. Arrhenius plots of the tempeRature dependence of the Rates constant are non-linear. The activation energy values at absolute zero have been computed using the Rates of relaxation under different experimental conditions. Thermodynamic parameters have also been calculated using the Rates of relaxation.
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effect of crosslinking agents basic chromium sulfate and formaldehyde on the thermal and thermomechanical stability of Rat Tail Tendon collagen fibre
Thermochimica Acta, 2000Co-Authors: R Usha, Thirumalachari RamasamiAbstract:The role of covalent and coordinate covalent crosslinks on the thermal and mechanical properties of Rat Tail Tendon (RTT) collagen fibre has been studied. The Tendons were tanned with formaldehyde (HCHO) and basic chromium sulfate (BCS). Thermal properties of the crosslinked fibres were studied using shrinkage tempeRature, hydrothermal isometric tension behaviour and differential scanning calorimetry (DSC). Mechanical properties were analysed using tensile strength and stress relaxation behaviour. The results show that BCS tanned RTT exhibits a marked increase in the peak tempeRature and enthalpy changes when compared to both native and HCHO tanned RTT. This may be due to a net increase in the number of intermolecular crosslinks arising from both electrovalent and coordinate covalent interactions during BCS tanning. After treatment with urea there is a decrease in the peak tempeRature and the enthalpy changes of BCS tanned RTT fibres suggesting alteRations in the secondary structure of collagen are possible even after tanning. An increased long range order is seen in the case of chromium tanned fibres in comparison to HCHO treated analogue.
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effect of ph on dimensional stability of Rat Tail Tendon collagen fiber
Journal of Applied Polymer Science, 2000Co-Authors: R Usha, Thirumalachari RamasamiAbstract:The organized molecular structure of collagen is related to its dimensional stability. The dimensional stability of collagen arises from the interplay of various intermolecular forces such as covalent, hydrogen bonding, electrostatic interactions, hydrophobic interactions, London or van der Waals forces, and weak interactions. A structure–function relationship exists in collagen. Electrostatic interactions play an important role in dimensional stabilization. The dimensional stability of Rat Tail Tendon (RTT) collagen fiber is affected by the change in the net fixed charge on the molecule as a function of pH. Thermal and mechanical properties are dependent on molecular and lattice orders. The pH dependence of thermal shrinkage, isometric tension, differential scanning calorimetry, swelling behavior, tensile strength, and percent extension and stress relaxation behavior are studied in 0.02M Tris-maleate buffer at pH 4–8. The observed experimental results provide compelling evidence that electrostatic interactions play an important role in the dimensional stability of RTT collagen. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1577–1584, 2000
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influence of hydrogen bond hydrophobic and electrovalent salt linkages on the transition tempeRature enthalpy and activation energy in Rat Tail Tendon rtt collagen fibre
Thermochimica Acta, 1999Co-Authors: R Usha, Thirumalachari RamasamiAbstract:Abstract The influence of hydrogen bonding, hydrophobic and electrostatic interactions on the thermal stability of Rat Tail Tendon collagen fibre has been studied using differential scanning calorimetry (DSC) and hydrothermal isometric tension (HIT) experiments. The reagents used to study these effects are urea (hydrogen bonding), aqueous alcohols (hydrophobic) and 0.02 M Tris-maleate buffer at pH 4–8 (electrostatic interactions). The peak tempeRature, enthalpy changes and energy of activation for collagen to gelatin transition are computed using DSC. The peak tempeRature and enthalpy changes decrease with increasing concentRations of urea, increasing chain length of alcohol and decreasing pH. The shape of the isometric tension curves of the collagen fibres provide information on the crosslinking of collagen fibre while the extent of relaxation after maximum tension is indicative of thermally stable crosslinks.
John J. Robinson - One of the best experts on this subject based on the ideXlab platform.
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compaRative analysis of the structure and thermal stability of sea urchin peristome and Rat Tail Tendon collagen
Journal of Cellular Biochemistry, 2002Co-Authors: Janice Mayne, John J. RobinsonAbstract:We have purified collagen from two distinct sources; the vertebRate, Rat Tail Tendon and an invertebRate, sea urchin adult tissue, the peristome. The collagenous nature of the purification products was confirmed by amino acid compositional analysis. Both prepaRations had high contents of glycine and proline residues and hydroxyproline was also present. The total pyrrolidine (proline+hydroxyproline) content decreased from 17.9 mole% in Rat Tail collagen to 12.9 mole% in peristome collagen. Distinctly different circular dichroic spectra were measured for these collagens. Analyses of spectra, measured as a function of tempeRature, revealed distinct thermal denatuRation profiles. The melting tempeRature for Rat Tail collagen was 38.5 degrees C, while the corresponding value for peristome collagen was significantly lower at 27 degrees C. A similar thermal denatuRation profile was obtained for Rat Tail collagen in digestion experiments using a 41-kDa gelatinase activity, isolated from sea urchin eggs. These results identify structural differences between a typical, vertebRate type I fibrillar collagen and an echinoderm collagen which serves as a constituent of a mutable connective tissue. These differences may relate to the functional roles played by collagen in these distinctly different tissues.
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compaRative analysis of the structure and thermal stability of sea urchin peristome and Rat Tail Tendon collagen
Journal of Cellular Biochemistry, 2002Co-Authors: Janice Mayne, John J. RobinsonAbstract:We have purified collagen from two distinct sources; the vertebRate, Rat Tail Tendon and an invertebRate, sea urchin adult tissue, the peristome. The collagenous nature of the purification products was confirmed by amino acid compositional analysis. Both prepaRations had high contents of glycine and proline residues and hydroxyproline was also present. The total pyrrolidine (proline + hydroxyproline) content decreased from 17.9 mole % in Rat Tail collagen to 12.9 mole % in peristome collagen. Distinctly different circular dichroic spectra were measured for these collagens. Analyses of spectra, measured as a function of tempeRature, revealed distinct thermal denatuRation profiles. The melting tempeRature for Rat Tail collagen was 38.5°C, while the corresponding value for peristome collagen was significantly lower at 27°C. A similar thermal denatuRation profile was obtained for Rat Tail collagen in digestion experiments using a 41-kDa gelatinase activity, isolated from sea urchin eggs. These results identify structural differences between a typical, vertebRate type I fibrillar collagen and an echinoderm collagen which serves as a constituent of a mutable connective tissue. These differences may relate to the functional roles played by collagen in these distinctly different tissues. J. Cell. Biochem. 84: 567–574, 2002. © 2001 Wiley-Liss, Inc.
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compaRative biochemical analysis of sea urchin peristome and Rat Tail Tendon collagen
Comparative Biochemistry and Physiology B, 1997Co-Authors: John J. RobinsonAbstract:Abstract We report here a biochemical comparison between type I Rat Tail Tendon collagen and collagen isolated from sea urchin peristome tissue. The sea urchin collagen consisted of two species of apparent mol masses, 140 and 116 kDa. Amino acid compositional analysis of the 140 and 116 kDa species revealed the presence of hydroxyproline and hydroxylysine as well as a glycine content of 28.1 mol.%. In solubility experiments the Rat Tail Tendon collagen was found to precipitate at sodium chloride concentRations between 1 and 2 M while peristome collagen remained soluble at salt concentRations as high as 4 M. Incubation of the peristome and Rat Tail Tendon collagen prepaRations with a sea urchin collagenase/gelatinase resulted in cleavage of the former but not the latter collagen. Upon heat denatuRation at 60°C, however, the Rat Tail Tendon collagen served as a substRate for the gelatinase. Cyanogen bromide cleavage of Rat Tail and peristome collagens geneRated largely unique peptide maps. Collectively, these results suggest that structural differences exist between echinoderm and vertebRate type 1 collagens.
