Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: DrugBank:APRD00216 (ABC)
 8,859 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ultrastructural identification and characterization of lung proteoglycans was studied using the polycationic dye, ruthenium red. Treating lung parenchyma with the detergent Triton X-100 increased epithelial permeability and allowed the dye to penetrate alveolar walls and stain the alveolar basement membrane and lung collagen. Ruthenium red stained numerous 10- to 40-nm granules concentrated at the lamina surface of basement membrane and attached to the major doublet collagen band. The granules attached to collagen were digested by chondroitinase ABC and papain, indicating that they represent proteoglycan aggregates containing chondroitin or dermatan sulfate. Granules observed on the alveolar basement membrane were resistant to digestion by collagenase and by all glycosidases, suggesting that heparin or heparan sulfate is the predominant glycosaminoglycan in epithelial basement membrane. Ruthenium red in association with tannic acid also stained a fine network of 3- to 10-nm filaments in which collagen was enmeshed, forming the interfibrillar matrix. This network was resistant to collagenase and glycosidase digestion but was removed after papain digestion, suggesting that it was a protein or glycoprotein that did not contain glycosaminoglycans. These methods have allowed visualization of lung proteoglycans and have identified a structure that does not contain glycosaminoglycan that is intimately associated with collagen. This technique can now be applied to explore the potential role of proteoglycans in lung development and in restructuring the lung in various disease states.
 ...
PMID:Ultrastructural localization and characterization of proteoglycans in the pulmonary alveolus. 9 9

Proteoglycan monomer (D1) and aggregate (A1) preparations were isolated from 4 M guanidinium chloride extracts of the Swarm rat chondrosarcoma. When EDTA, 6-aminohexanoic acid, and benzamidine were present in the solutions, the D1 preparation contained a single component (SO = 23 S), and the A1 preparation contained 30% monomer (SO = 23 S) and 70 percent aggregate (SO = 111 S). In the absence of EDTA, 6-aminohexanoic acid, and benzamidine, the A1 preparations contained only small proteoglycan fragments, indicating that extensive enzymatic degradation had occurred. The composition of the proteoglycan monomer was different from that of proteoglycan monomer preparations from normal hyaline cartilages in that it did not contain keratan sulfate and chondroitin 6-sulfate; only chondroitin 4-sulfate was found. The A1 preparation from the chondrosarcoma contained only one link protein, which was like the smaller (molecular weight of 40,000) of the two link proteins present in A1 preparations from bovine nasal cartilage. When the A1 preparation from the chondrosarcoma was treated with chondroitinase ABC and trypsin and the digest was chromatographed on Sepharose 2B, a complex was isolated which contained the link protein and the segments of the protein core from the hyaluronic acid-binding region of the proteoglycan molecules.
 ...
PMID:Isolation and characterization of proteoglycans from the swarm rat chondrosarcoma. 12 82

1. Rat tail-tendon collagen was coupled to activated Sepharose 4B at 2.5 mg of collagen/ml of gel. Chromatographic columns of this gel were calibrated with T2 virus (Vo) and Dnp-alanine (Vt). 2. The chromatographic behaviour of cartilage proteoglycans on the collagen-substituted gel was studied under conditions of varying ionic strength. Proteoglycan subunit obtained from bovine nasal cartilage, the proteoglycan obtained after digestion with chondroitnase ABC and purified chondriotin sulphate were all retarded on the collagen gel by an interaction that abolished at I0.17. Purified keratan sulphate and hyaluronic acid were not retarded. 3. A strong ionic interaction between cartilage proteoglycan and collagen was demonstrated to depend on the structure of the protein core of the proteoglycan.
 ...
PMID:Interaction of cartilage proteoglycans with collagen-substituted agarose gels. 12 83

Incorporation of sulfate into alcian blue-precipitable glycosaminoglycan of 12-day-old chick embryo sterna is stimulated by addition, separately or together, of normal human serum and physiological concentrations of thyroid hormones (Audhya, T.K., and Gibson, K.D. (1975) Proc. Natl. Acad, Sci. U. S. A. 72, 604--608). We present evidence that this stimulation is due to increased synthesis of at least one proteoglycan, with minor alterations in the size and chemical composition of the glycosaminoglycans. Pulse-chase experiments showed no detectable loss of label during the chase, in control sterna or sterna incubated with serum and L-3,5,3'-triiodothyronine; thus, all incorporation was the result of synthesis of glycosaminoglycans. In double-label experiments, with 35SO4(2-) and [3H]acetate, the molar ratio of 3H and 35S incorporated into glycosaminoglycans was changed little, if at all, by addition of serum or triiodothyronine or both, at concentrations which increased incorporation up to 2-fold. Glycosaminoglycans isolated from these and other incubations gave similar elution patterns from agarose columns, and identical electrophoretic patterns on cellulose acetate. Digestion with chondroitinase ABC (chondroitin ABC lyase; EC 4.2.2.4.) showed that incorporation was into chondroitin sulfate and possibly hyaluronic acid, and that the proportions of non-sulfated, 4-sulfated, and 6-sulfated disaccharide units differed little between stimulated and unstimulated sterna. Incorporation of [3H]serine into glycosaminoglycans from papain digest of sterna paralleled incorporation of 35SO4(2-), and indicated a number average molecular weight between 21,000 and 25,000 for the newly synthesized chondroitin sulfate. This value was confirmed by gel filtration chromatography, which also showed that the average molecular weight of the newly synthesized chondroitin sulfate decreased up to 15% under conditions of 2-fold stimulation. Proteoglycans were extracted from sterna incubated with [3H]serine and 35SO4(2-) and analyzed by isopycinic centrifugation in CsCl and by zone sedimentation in a sucrose gradient. A major proteoglycan fraction could be separated by either method. Incorporation of both isotopes into this proteoglycan fraction, and into glycosaminoglycans isolated after papain digestion, was stimulated in a coordinate manner. Almost identical results were obtained with both separation techniques. The results indicate that the synthesis of the major proteoglycan, and probably also of a minor one, is stimulated by serum and triiodothyronine.
 ...
PMID:Stimulation of proteoglycan synthesis in chick embryo sternum by serum and L-3,5,3'-triiodothyronine. 13 41

Rat liver cells grown in primary cultures in the presence of [(35)S]sulphate synthesize a labelled heparan sulphate-like glycosaminoglycan. The characterization of the polysaccharide as heparan sulphate is based on its resistance to digestion with chondroitinase ABC or hyaluronidase and its susceptibility to HNO(2) treatment. The sulphate groups (including sulphamino and ester sulphate groups) are distributed along the polymer in the characteristic block fashion. In (3)H-labelled heparan sulphate, isolated after incubation of the cells with [(3)H]galactose, 40% of the radioactive uronic acid units are l-iduronic acid, the remainder being d-glucuronic acid. The location of heparan sulphate at the rat liver cell surface is demonstrated; part of the labelled polysaccharide can be removed from the cells by mild treatment with trypsin or heparitinase. Further, a purified plasma-membrane fraction isolated from rats previously injected with [(35)S]sulphate contains radioactively labelled heparan sulphate. A proteoglycan macromolecule composed of heparan sulphate chains attached to a protein core can be solubilized from the membrane fraction by extraction with 6m-guanidinium chloride. The proteoglycan structure is degraded by treatment with papain, Pronase or alkali. The production of heparan [(35)S]sulphate by rat liver cells incubated in the presence of [(35)S]sulphate was followed. Initially the amount of labelled polysaccharide increased with increasing incubation time. However, after 10h of incubation a steady state was reached where biosynthetic and degradative processes were in balance.
 ...
PMID:Structure and metabolism of rat liver heparan sulphate. 14 28

Proteoglycans were extracted from bovine articular cartilage with guanidine-HCl and fractionated in cesium chloride density gradients by equilibrium ultracentrifugation. The acidic glycosaminoglycan (AGAG) components were then determined enzymatically with chondroitinase-ABC and streptomyces hyaluronidase. Under associative and dissociative conditions, the distribution of the AGAG components was as follows: the ratio of 4-sulfated disaccharide units to total AGAG increased with decreasing density gradients whereas that of 6-sulfated disaccharide units to total AGAG increased with increasing density gradients. The ratio of disulfated disaccharide units to total AGAG increased somewhat with decreasing density gradients whereas that of non-sulfated disaccharide units tended to decrease. Although the cartilage proteoglycan macromolecules were heterogeneous, a certain regularity was observed with respect to the distribution of sulfate and the degree of sulfation in the chondroitin sulfate chains of the proteoglycans.
 ...
PMID:Constitutional heterogeneity of the glycosaminoglycans in articular cartilage proteoglycans. 14 4

Fibronectin is a major surface protein of normal animal cells but is absent from many transformed cells. Addition of fibronectin to transformed cells causes increased cell substrate adhesion and changes in the morphology and cytoskeleton of the cells. We have coupled fibronectin to photoactivable chemical cross-linkers and have added it to cells to identify those molecules to which it binds. In this way, fibronectin can be cross-linked to sulfated proteoglycans at the cell surface. The cross-linking is specific for fibronectin. The fibronectin-proteoglycan complex is sensitive to chondroitinase ABC and AC and to trypsin. Addition of fibronectin also affects binding of hyaluronic acid to the cells. These results suggest that fibronectin interacts with proteoglycans at the cell surface. The existence of such interactions may have implications for the role of fibronectin and proteoglycans in cell adhesion.
 ...
PMID:Cross-linking of fibronectin to sulfated proteoglycans at the cell surface. 22 72

The distribution of glycosaminoglycans and glycoproteins has been studied in cytoplasmic and particulate fractions of neurons isolated in bulk from rat cerebrum. Lysis of the neurons in 25 mM sodium phosphate buffer at pH 7.5 released 20% of the protein and over 90% of the lactate dehydrogenase in a soluble form. Eighty-two percent of the chondroitin sulfate was also released, together with 55% of the heparan sulfate and 24-25% of the hyaluronic acid and glycoproteins. The chondroitin sulfate remaining in the membranes was completely depolymerized to disaccharides after treatment with chondroitinase ABC, and treatment of the neuronal membranes with 0.1% trypsin removed 55-63% of the chondroitin sulfate and heparan sulfate but only 25% of the sulfated glycoproteins. The results reported here support our previous conclusion that the soluble chondroitin sulfate proteoglycan of brain is largely a cytoplasmic constitutent of neurons (and astrocytes) and is not primarily present in nervous tissue as an extracellular ground substance.
 ...
PMID:Presence of chondroitin sulfate in the neuronal cytoplasm. 28 11

Rabbit platelets were labeled in vivo with 35S for characterization of platelet sulfated glycosaminoglycan. When rabbit platelets were aggregated by ADP, sulfated proteoglycan was lost from the platelet surface although no release of granule contents occurred. The sulfated proteoglycan contained in the granules of platelets pretreated with ADP was subsequently released by treatment with thrombin. The 35S-labeled proteoglycan from both sources was isolated by gel filtration and the glycosaminoglycan portion of the proteoglycan was characterized as chondroitin 4-sulfate by examining the products of digestion with hyaluronidase, chondroitinase AC and ABC, and chondro-4- and 6-sulfatases; by identification of the hexosamine as N-acetylgalactosamine; by determination of a 1 : 1 : 1 molar ratio of N-acetylgalactosamine, uronic acid and inorganic sulfate; and by cetylpyridinium chloride cellulose chromatography. In these studies, the use of 35S-labeled proteoglycan made possible detection and quantification of much smaller amounts of material than would be possible with unlabeled material. Chondroitin 4-sulfate was the only sulfated glycosaminoglycan identified in the proteoglycan lost from the platelet surface during ADP-induced aggregation and in the proteoglycan released from the granules when the platelets were exposed to thrombin.
 ...
PMID:Characterization of the sulfated glycosaminoglycan on the surface and in the storage granules of rabbit platelets. 44 61

Proteoglycans isolated under associative conditions in the presence of protease inhibitors from human nucleus pulposus contained 17% aggregate and 83% non-aggregating monomer (Kav = 0.5 on Sepharose CL-2B). Isolated aggregate after reduction and alkylation was resolved into two components (Kav = 0.15 and 0.43) on Sepharose CL-2B. Labeled proteoglycans isolated from parallel samples pulsed with [35S]sulfate and chased for up to 18 h were present largely as aggregated material (up to 78%). Reduction and alkylation of the labeled samples gave a labeled proteoglycan monomer with Kav = 0.15. Both the labeled and unlabeled chondroitin sulfate chains had the same distribution on Sepharose CL-6B and equivalent molecular weights (Mr = 2.0 x 10(3)). After chondroitinase ABC digestion, the unlabeled keratan sulfate-protein core was polydisperse with a Kav = 0.38 on Sepharose CL-4B while the labeled keratan sulfate-protein core had a Kav = 0.05. This indicates that the newly synthesized proteoglycan had a large core protein and suggests that the proteoglycans present in nucleus pulposus are originally synthesized as large molecular weight, aggregating proteoglycans.
 ...
PMID:Aggregated proteoglycan synthesis in organ cultures of human nucleus pulposus. 50 May 96


1 2 3 4 5 6 7 8 9 10 Next >>