Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.6.4 (chondroitinase)
 2,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A study of human articular cartilage indicated that componenet proteoglycans can be phosphorylated. Phosphorylation, also found in a specimen of human epiphysial cartilage, occurred when [gamma-32P]-ATP or 32Pi was included in the in vitro incubation medium. Treatment of the phosphorylated proteoglycans with chondroitinase and chondrosulfatases effectively removed the chondroitin sulfate without dephosphorylating the remaining molecule. Since phosphorylation could be effected in a totally chemically defined medium, it appears that the necessary enzyme systems for this reaction are contained entirely within chondrocytes.
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PMID:Phosphorylation of proteoglycans in human articular cartilage. 15 Sep 63

Bovine adrenal chromaffin cells were incubated with inorganic thiophosphate, using a protocol similar to experiments with inorganic phosphate, in order to determine the source of previously observed thiophosphoproteins. Incubation of cultured cells with [35S]thiophosphate resulted in its incorporation into cell constituents within 2 min. SDS-PAGE of the treated cells showed incorporation of label into a broad 97-121 kDa band that was evident after 5 min of treatment and increased progressively to the 40 min exposure limit. Monolayers of chronically treated cells were fractionated into subcellular constituents. The only particulate fraction containing radiolabelled proteins was the chromaffin vesicle fraction. Two-dimensional electrophoresis of the treated cells and isolated chromaffin vesicles showed a majority of proteins in the acidic region of the first dimension gel. A fluorogram of the gel revealed two regions of radiolabelled proteins at acidic and neutral regions of the 2-D gel. These were within the boundaries of the 97-121 kDa band. The thiophosphorylated proteins were released as soluble proteins upon osmotic or freeze-thaw lysis of the vesicles. Chromaffin vesicles isolated from either cultured cells or adrenal medulla tissue were energized by 2 mM ATP but not by the analog adenosine 5'-O-(3-thiotriphosphate). The 97-121 kDa proteins in intact or lysed vesicles prepared from adrenal medulla tissue were not thiophosphorylated by either inorganic thiophosphate or adenosine 5'-O-(3-thiotriphosphate) in the presence or absence of energization by ATP. Nearly complete loss of radiolabel from matrix proteins treated with chondroitinase ABC suggests that it is a component of vesicle proteolgycans.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thiophosphorylated proteins in chromaffin cells are chromaffin vesicle matrix proteins. 130 66

Purified proteoglycan subunits from human articular, bovine articular and nasal cartilages, and a rat chondrosarcoma were phosphorylated in vitro by beef heart cAMP-dependent protein kinase in the presence of gamma 32P-ATP. In these experiments, a maximum of 1.7 moles of 32P were incorporated per mole of proteoglycan from human cartilage. Phosphorylation was dependent on the presence of cAMP. Analysis by autoradiography revealed that serine residues in the core protein of the proteoglycan were the sites of phosphorylation. Treatment of proteoglycan subunits with chondroitinase ABC and alkaline phosphatase prior to reaction with cAMP-dependent protein kinase increased the incorporation of 32P by 12-30% when compared with untreated proteoglycans. These data indicate that proteoglycans in cartilage can be phosphorylated by cAMP-dependent protein kinase.
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PMID:Phosphorylation of proteoglycans from human articular cartilage by a cAMP-dependent protein kinase. 647 53

Type VI collagen was once considered a minor collagen, but now it is known as a major component of the extracellular matrices of most tissues. Type VI collagen tetramers aggregate into beaded filaments with repeats of approximately 100 nm, and the beaded filaments align laterally to form type VI collagen periodic fibrils by incubation with acidic ATP solution. Polyanionic ATP could cause lateral alignment of type VI collagen beaded filaments. Since the periodic structure is observable by transmission electron microscopy, we can examine the tissue distribution of type VI collagen by ATP treatment. Moreover, the interaction of type VI collagen with other extracellular matrix components can be examined by combining ruthenium red (RR) staining, which specifically interacts with tissue glycosaminoglycans (GAGs), with the ATP treatment. I here describe the localization and possible function of type VI collagen examined in our laboratory. After ATP incubation, numerous type VI collagen periodic fibrils appeared closely associated with striated collagen fibrils (mouse cornea and fibrous layer of mandibular condyle), with trophoblastic and endothelial basal lamina (human placenta), or with cell surface of fibroblasts (mouse tendon) and synovial cells (mouse synovium). The dark bands of the type VI collagen periodic fibrils were stained by RR, indicating the association of proteoglycans (PGs)/GAGs with this collagen. If the mouse corneal tissue was digested with chondroitinase ABC or testicular hyaluronidase prior to ATP treatment, type VI collagens were segregated to form periodic structures apart from striated collagen fibrils. In the mouse mandibular condyle, hyaluronidase digestion before ATP treatment caused unmasking of type VI collagen.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Tissue localization and possible function of type VI collagen]. 854 Feb 77