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)

An improved device for potentiometry using magnetic circular dichroism spectroscopy has been developed and used to characterize the potentiometric behavior of solubilized beef heart cytochrome oxidase. In the absence of inhibitors, the electron affinity of cytochromes alpha and alpha 3 are indistinguishable and adequately described by the allosteric model of Nicholls and Peterson (Nicholls, P., and Peterson, L. C. (1972) Biochim. Biophys. Acta 357, 462-467). All of the cytochrome alpha can be accounted for as low spin heme throughout the titration. Cytochrome c present at 1:1, 2:1, and 4:1 stoichiometry with cytochrome alpha did not significantly affect the potentiometric behavior of alpha or chondroitinase alpha 3; at the 1:1 ratio the midpoint potential of cytochrome c was lowered by about 30 mV. In the presence of formate, azide and cyanide cytochrome alpha assumed approximately n = 1 behavior. However, the response of alpha 3 differed with each reagent and was particularly complex in the presence of azide. Fluoride produced very small changes in the potentiometric behavior suggesting that it may not be a ligand to cytochrome alpha 3. Possible deficiencies in the allosteric model are examined.
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PMID:Further characterization of the potentiometric behavior of cytochrome oxidase. Cytochrome alpha stays low spin during oxidation and reduction. 631 78

Fluid, Na+ and Cl- content and distribution have been examined in incubated segments of thoracic and abdominal aorta from male Wistar rats aged 1, 3 and 18 months. Na+ and Cl- were determined under conditions of total metabolic blockade (cyanide + iodoacetate). The total aortic mural fluid content, relative to solute-free dry weight, fell from 1 to 3 months, due mainly to relative contraction of the extracellular (e.c.) (inulin) space. It increased from 3 to 18 months due mainly to an increased intracellular (i.c.) (non-inulin) space. Total mural free and bound Na+ content, as well as i.c. Na+ content and concentration, fell from 1 to 3 months and increased from 3 to 18 months. No bound Na+ was detectable in segments which had been incubated in the presence of chondroitinase ABC. I.c. Cl- content and concentration fell from 1 to 3 months, but thereafter did not alter significantly. Bound Cl- in the aortic wall of 3-month-old rats was markedly reduced by incubation in the presence of a non-specific protease preceded by treatment with glycerol. The results are discussed in relation to previously established age-related characteristics of aortic and arterial walls.
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PMID:The influence of age on fluid and sodium chloride distribution in rat aortic wall. 639 87

In order to study the temporal and topological events involved in the processing and assembly of chondroitin sulfate proteoglycan, a fractionation scheme involving differential centrifugation and discontinuous sucrose density gradient centrifugation was developed for homogenates of chick embryo sternal chondrocytes. The precursors in these subcellular fractions were examined by a series of pulse, pulse-chase, and continuous labeling experiments. When chondrocytes were pulsed for 20 min with [35S]methionine, an immunoprecipitable core protein precursor with an approximate molecular size of 376,000 Da was localized to the rough endoplasmic reticulum fractions. Further incubation under chase conditions showed the presence of the 376,000-Da species as well as two additional polypeptides of higher molecular masses in the smooth membrane-enriched fractions within the next 2 h. This translocation did not occur in the presence of the energy transfer inhibitor carbonyl cyanide-m-chlorophenylhydrazone. The labeling pattern of the newly synthesized core protein precursor with either [3H] mannose or [3H]glucosamine showed that N-linked oligosaccharide addition was found on the earliest synthesized product in the rough endoplasmic reticulum, and the addition of this oligosaccharide was inhibited by co-incubation with tunicamycin. Furthermore, the high mannose oligosaccharide was susceptible to cleavage by endo-beta-N-acetylglucosaminidase H, while upon chase approximately 56 and 31% of the glucosamine- and mannose-labeled oligosaccharides, respectively, were processed to resistant forms, presumably in the Golgi complex. Both direct assay of glycosyl- and sulfotransferases requisite for addition of chondroitin sulfate chains and sensitivity of intracellular precursors to chondroitinase, keratanase , and endoglycosidase H suggest that only the N-linked oligosaccharides are added in the rough endoplasmic reticulum and glycosaminoglycan chain addition occurs predominantly in smooth membranes.
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PMID:Subcellular localization of the synthesis and glycosylation of chondroitin sulfate proteoglycan core protein. 672 88