scholarly journals The origin of human cartilage proteoglycan link-protein heterogeneity and fragmentation during aging

1985 ◽  
Vol 232 (3) ◽  
pp. 805-812 ◽  
Author(s):  
J S Mort ◽  
B Caterson ◽  
A R Poole ◽  
P J Roughley
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Human Articular Cartilage ◽  
Human Cartilage ◽  
Link Protein ◽  
Cartilage Proteoglycan ◽  
Disulphide Bonds ◽  
Single Link ◽  
Chemical Deglycosylation

Human articular-cartilage link proteins are resolved into three components by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, indicative of three different structures. The action of the proteinase clostripain yields a single link-protein component with electrophoretic properties analogous to those of the smallest (most mobile) native link protein, suggesting that this link protein may be derived naturally from one or both of the larger molecules by proteolytic cleavage in situ. Upon chemical deglycosylation of native link protein two components are resolved, suggesting that two of the link proteins differ only in their degree and/or type of oligosaccharide substitution. This pattern is compatible with a proteolytic origin for the smallest link protein. During aging further proteolytic fragmentation occurs, though it is only apparent on reduction of disulphide bonds. This fragmentation occurs at identical sites in all three native link proteins, indicating the existence of a large region common to all the link proteins, which appears to consist predominantly of the C-terminal half of the molecules. These observations are compatible with the variation in oligosaccharide and proteolytic heterogeneity occurring at the N-terminus of the link proteins.

scholarly journals Immunochemistry of cartilage proteoglycan. Immunodiffusion and gel-electrophoretic studies

1972 ◽  
Vol 126 (1) ◽  
pp. 163-169 ◽  
Author(s):  
H Keiser ◽  
H J. Shulman ◽  
J I. Sandson
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Additional Species ◽  
Link Protein ◽  
Nasal Cartilage ◽  
Caesium Chloride ◽  
Cartilage Proteoglycan ◽  
Core Proteins ◽  
Specific Antigens ◽  
Species Specific

Cartilage proteoglycan is thought to be composed of subunits, core proteins with covalently attached sulphated polysaccharide side chains, which form aggregates by non-covalent association with a link protein. The new technique of non-disruptive extraction followed by fractionation in caesium chloride gradients provides a useful means of preparing relatively pure proteoglycan aggregate, subunit and link fractions. Immunological studies of these fractions led to the identification of an antigen associated with the proteoglycan subunit which was common to several species and to the demonstration of additional species-specific antigens in aggregate and link fractions derived from bovine nasal cartilage. Polyacrylamide-gel electrophoresis with sodium dodecyl sulphate of bovine proteoglycan aggregate and link fractions gave two protein bands in the gels and a protein–polysaccharide band at the origin; subunit fractions gave only the band at the origin. These results are consistent with the current concept of cartilage proteoglycan structure.

scholarly journals Age-related changes in protein-related epitopes of human articular-cartilage proteoglycans

1986 ◽  
Vol 236 (1) ◽  
pp. 71-75 ◽  
Author(s):  
T T Glant ◽  
K Mikecz ◽  
P J Roughley ◽  
E Buzás ◽  
A R Poole
Keyword(s):  
Core Protein ◽  
Buoyant Density ◽  
Human Articular Cartilage ◽  
Human Cartilage ◽  
Keratan Sulphate ◽  
Cartilage Proteoglycan ◽  
Age Related ◽  
Age Dependent ◽  
Old Adult ◽  
Cartilage Proteoglycans

Monoclonal antibodies were prepared that recognize different age-related epitopes on proteoglycan subunits of high buoyant density isolated from human epiphysial and articular cartilages. Antibody EFG-4 (IgG1) recognizes a proteinase-sensitive segment associated with the core protein. Antibody BCD-4 (IgG1) reacts with keratan sulphate bound to core protein. Both epitopes are minimally expressed in foetal cartilage and increase with age after birth to become maximally expressed in adult cartilage by about 30 years of age. In contrast, monoclonal antibody alpha HFPG-846 (IgM) recognizes a core-protein-related epitope that is maximally expressed in young foetal cartilage, declines up to birth and thereafter and is almost absent after about 30 years of age. Antibody alpha HFPG-846 was used to isolate by immuno-affinity chromatography two subpopulations of proteoglycan subunits from a 16-year-old-human cartilage proteoglycan subunit preparation. Only the antibody-unbound population showed a significant reaction with antibodies EGF-4 and BCD-4. The amino acid and carbohydrate compositions of these proteoglycan fractions were different, and one (antibody-bound) resembled those of foetal and the other (antibody-unbound) resembled those of adult proteoglycans isolated from 24-27-week-old-foetal and 52-56-year-old-adult cartilage respectively. These observations demonstrate that human cartilages contain at least two chemically and immunochemically distinct populations of proteoglycans, the proportions and content of which are age-dependent. It is likely that these populations represent the products of different genes, though their heterogeneity may be compounded by the result of different post-translation modifications.

scholarly journals Detection of disulphide bonds and localization of interchain linkages in the third (C3) and the fourth (C4) components of human complement

1986 ◽  
Vol 233 (3) ◽  
pp. 819-825 ◽  
Author(s):  
J Janatova
Keyword(s):  
Binding Sites ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polyacrylamide Gel ◽  
Gamma Chain ◽  
Complement Components ◽  
The Third ◽  
Disulphide Bonds ◽  
Reduced State

Disulphide bonds contribute significantly to the maintenance of structural/functional integrity of many proteins. Therefore it was of interest to study the distribution and the effect of disulphides on conformation of complement components C3 and C4. These proteins are precursors of several fragments with various binding sites and distinct physiological functions. The constituents of C3c (beta, alpha 27, alpha 43) and those of C4c (beta, alpha 27, alpha 16, gamma) were investigated, since other fragments of C3 or C4 do not participate in interchain linkages. Inter-and intra-chain disulphide bonds in C3c and C4c were localized by using a modification of conventional SDS (sodium dodecyl sulphate)/polyacrylamide-gel electrophoresis such that the change in mobility of disulphide-bond-containing proteins can be detected throughout the transition from a non-reduced to a fully reduced state. Several forms of the alpha 43 fragment from C3, and of the gamma-chain of C4, with different mobilities can exist, depending on the number of intra-chain disulphide bonds reduced. The intermediates (heterodimers) generated by a partial reduction of C3c or C4c were characterized by two-dimensional SDS/polyacrylamide-gel electrophoresis performed in the absence, then in the presence, of beta-mercaptoethanol. The inter-chain linkages in C3c were determined to be beta-alpha 27 and alpha 27- alpha 43, thus indicating the presence of only one interchain bond in C3. The two interchain bonds in C4c are beta-alpha 27 and alpha 16-gamma. The third interchain bond in C4 (alpha 27-gamma, tentative) remains to be determined.

scholarly journals A study of equilibrium binding of link protein to hyaluronate

1983 ◽  
Vol 213 (2) ◽  
pp. 445-450 ◽  
Author(s):  
M Lyon ◽  
I A Nieduszynski
Keyword(s):  
Dissociation Constants ◽  
Gradient Centrifugation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Protein Molecule ◽  
Gel Chromatography ◽  
Guanidinium Chloride ◽  
Link Protein ◽  
Equilibrium Binding ◽  
Femoral Head Cartilage

Link protein was extracted from bovine femoral-head cartilage, radiolabelled while in the proteoglycan-aggregate stage, and then purified by density-gradient centrifugation and gel chromatography. The purity of the preparation was assessed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and two species with approx. mol.wts. 45000 and 48000 were observed. Sedimentation-velocity experiments were performed in 0.5 M-guanidinium chloride/5 mM-phosphate, pH 7.4, and yielded an SO20, w of 4.75S. The proportion of link protein unable to interact with hyaluronate was determined by chromatography on Sepharose CL-4B. The binding of link protein to high-molecular-weight hyaluronate was studied by frontal-gel chromatography on Sepharose CL-4B in 0.5 M-guanidinium chloride/5 mM-phosphate/0.1% bovine serum albumin, pH 7.4. Experiments were performed at 10, 17 and 25 degrees C and the results were treated as described by Scatchard [(1949) Ann. N.Y. Acad. Sci. 51, 660-672]. Dissociation constants of approx. (1-4) X 10(-8) M were obtained. The length of hyaluronate occupied per link-protein molecule was determined to be six to seven disaccharides.

scholarly journals Treatment of cartilage proteoglycan aggregate with hydrogen peroxide. Relationship between observed degradation products and those that occur naturally during aging

1987 ◽  
Vol 247 (2) ◽  
pp. 349-357 ◽  
Author(s):  
C R Roberts ◽  
J S Mort ◽  
P J Roughley
Keyword(s):  
Transition Metal ◽  
Metal Ion ◽  
Core Protein ◽  
Degradation Products ◽  
Transition Metal Ions ◽  
Human Articular Cartilage ◽  
Human Aging ◽  
Human Cartilage ◽  
Cartilage Proteoglycan ◽  
Age Related

The effects of treatment of purified neonatal human articular-cartilage proteoglycan aggregate with H2O2 were studied. (1) Exposure of proteoglycan aggregate to H2O2 resulted in depolymerization of the aggregate and modification of the core protein of both the proteoglycan subunits and the link proteins. (2) Treatment of the proteoglycan aggregate with H2O2 rendered the proteoglycan subunits unable to interact with hyaluronic acid, with minimal change in their hydrodynamic size. (3) Specific cleavages of the neonatal link proteins occurred. The order in which the major products were generated and their electrophoretic mobilities resembled the pattern observed during human aging. (4) The proteolytic changes in the link proteins were inhibited in the presence of transition-metal-ion chelators, thiourea or tetramethylurea, suggesting that generation of hydroxyl radicals from H2O2 by trace transition-metal ions via a site-specific Fenton reaction may be responsible for the selective cleavages observed. (5) Cleavage of the link proteins in proteoglycan aggregates by H2O2 was shown to have a limited effect on the susceptibility of these proteins to cleavage by trypsin. (6) The relationship between these changes and those observed in cartilage during human aging suggests that some of the age-related changes in the structure of human cartilage proteoglycan aggregate may be the result of radical-mediated damage.

scholarly journals The action of human articular-cartilage metalloproteinase on proteoglycan and link protein. Similarities between products of degradation in situ and in vitro

1986 ◽  
Vol 237 (1) ◽  
pp. 117-122 ◽  
Author(s):  
I K Campbell ◽  
P J Roughley ◽  
J S Mort
Keyword(s):  
Hyaluronic Acid ◽  
Articular Cartilage ◽  
Interleukin 1 ◽  
Human Articular Cartilage ◽  
Link Protein ◽  
Protein Components ◽  
Stimulation Of ◽  
Hyaluronic Acid Binding

Interleukin 1 stimulation of human articular cartilage in organ culture produced the concomitant release of proteoglycan fragments and latent metalloproteinase. The released fragments ranged in size from that of almost intact proteoglycan subunits to the product of limiting digestion generated by the activated metalloproteinase. None of the fragments possessed the ability to interact with hyaluronic acid. Analysis of proteoglycan aggregate digested with the activated metalloproteinase showed that isolated hyaluronic acid-binding regions were produced from the proteoglycan subunits, and that the two higher-Mr link-protein components (Mr 48,000 and 44,000) were converted into the lowest-Mr component (Mr 41,000). Link protein extracted from cartilage under stimulation with interleukin 1 showed a similar conversion. These results suggest that interleukin 1 stimulates the release of latent metalloproteinase from chondrocytes and that a proportion of the enzyme is activated in situ in the cartilage matrix. The mode of action of the activated enzyme is compatible with a role in the changes in proteoglycan structure seen in aging.

scholarly journals A comparative study of the binding of cartilage link protein and the hyaluronate-binding region of the cartilage proteoglycan to hyaluronate-substituted Sepharose gel

1981 ◽  
Vol 199 (2) ◽  
pp. 297-305 ◽  
Author(s):  
A Tengblad
Keyword(s):  
Time Course ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Binding Constants ◽  
Minimum Size ◽  
Gel Chromatography ◽  
Binding Region ◽  
Link Protein ◽  
Nasal Cartilage ◽  
Number Of Binding Sites

The hyaluronate-binding proteins from bovine nasal cartilage, i.e. the hyaluronate-binding region of the proteoglycan and the link protein, were labelled with 125I and separated from each other by gel chromatography. The proteins were characterized by molecular-weight determinations and their purity was established by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and immunodiffusion. The binding properties of the two proteins by hyaluronate-substituted Sepharose gel were compared. It was found that both proteins behaved similarly. They bound with the same efficiency to the gel, they showed the same time course of binding, had slightly different pH optima for binding and both proteins had a decreasing affinity for the gel with increasing ionic strength. The binding to the gel could be inhibited by soluble hyaluronate, and the minimum size of a hyaluronate oligosaccharide required for inhibition was in both cases a decasaccharide (only even-numbered oligosaccharides were tested). The proteins did not show any co-operative binding in the system tested, which could be explained by the large number of binding sites in the hyaluronate-substituted gel. Binding constants for the protein-hyaluronate interaction were estimated. A value of 1.3 x 10(7) M-1 was obtained for the hyaluronate-binding region of the proteoglycan, in agreement with literature data. The corresponding value for the link protein was 0.7 x 10(7) M-1.

Demonstration of in situ fibrin degradation in pathologic thrombi

Blood ◽  
1984 ◽  
Vol 63 (5) ◽  
pp. 1216-1224
Author(s):  
CW Francis ◽  
RE Jr Markham ◽  
VJ Marder
Keyword(s):  
Polypeptide Chain ◽  
Dynamic Equilibrium ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Aortic Aneurysms ◽  
Gamma Chain ◽  
Chain Composition ◽  
Vascular Obstruction

Fibrin prepared from 15 pathologic thrombi was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine the extent and pattern of fibrinolysis that occurs in vivo. Two groups of patients could be distinguished on the basis of the polypeptide chain composition of fibrin in their thrombi. Those patients who presented with acute vascular obstruction, either arterial or venous, showed a minimal degree of fibrin degradation, with a dominance of intact, undegraded crosslinked gamma-gamma dimers. On the other hand, patients with long-standing symptoms associated with chronic aortic aneurysms had thrombi containing extensively degraded fibrin. Thrombi in large aortic aneurysms were dissected into concentric layers that showed different degrees of fibrinolysis. The luminal surface consisted of fresh, red thrombus and contained undegraded crosslinked fibrin similar to that found in patients with acute occlusive disease. Deeper layers of the thrombus showed gamma-gamma chain degradation throughout, indicating that this portion was undergoing active thrombolysis. The findings demonstrate that the variability in the pathophysiologic balance between coagulation and fibrinolysis is reflected in vivo by the polypeptide chain composition of crosslinked fibrin in thrombi. The results support the hypothesis of a dynamic equilibrium between clotting and lysis, but indicate that the balance between these two processes may be distinctly different in separate areas of a single clot.

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