1,720,982 research outputs found
GLYCOSAMINOGLYCANS AND PROTEINS - DIFFERENT BEHAVIORS IN HIGH-PERFORMANCE SIZE-EXCLUSION CHROMATOGRAPHY
No full textThe influence of the conformation of globular proteins and glycosaminoglycans in high-performance size-exclusion chromatography (HPSEC) was studied. Glycosaminoglycans (heparin, chondroitin sulphate and dermatan sulphate) with different primary structures, sulphate-to-carboxyl ratios and physico-chemical properties were extracted and purified. Their physico-chemical properties and purity were evaluated by several analytical techniques. Glycosaminoglycans with different relative molecular masses (M(r)) were prepared by a chemical depolymerization process. These heteropolysaccharides were evaluated by HPSEC and compared with globular proteins of known relative molecular mass. The two third-degree polynomial regression curves for proteins and glycosaminoglycans have different coefficients and the columns present different exclusion limits. In particular, under the experimental conditions, the M(r) exclusion limits for high M(r) are 44 000 for glycosaminoglycans and 240 000 for globular proteins. In contrast, the behaviours of these two classes of macromolecules are similar for lower M(r). In fact, the two third-degree polynomial curves show the same regression below about M(r) = 1000. The behaviour in HPSEC is discussed in relation to the different steric conformations for proteins and glycosaminoglycans with different relative molecular masses
COMPETITIVE-INHIBITION OF MYOSIN ATPASE ACTIVITY BY DIFFERENT MOLECULAR-WEIGHT HEPARINS
No full textMyosin ATPase activity was measured, by continuous luminometric method, in presence of different molecular weight heparins. ATPase activity decreases in thè presence of heparin, when simultaneous incubation with ATP is carried out; thè percentage of inhibition is proportional to polysaccharide concentration. Heparins of different molecular weights (1.75 KD to 11.6 KD) are competitive inhibitors of enzymatìc activity; thè inhibitory effects is also appreciable with trisulphated disaccharide.The possible mechanisms of interactìon between heparin and myosin ATPase are discussed
EFFECTS OF DIFFERENT GLYCOSAMINOGLYCANS ON MYOSIN ATPASE ACTIVITY IN PLATELETS
No full textHeparin is well known for increasing microvascular bleeding and capillary permeability [1]. Heparin also affects many functional characteristics of platelets, such as agonist-induced aggregation, piatele! adhesion [2], release of serotonin, thromboglobulin and PF4 [3]. Furthermore, heparin induces thrombocytopenia [4], prolongs thè bleeding lime in patients and has antithrombotic activity [5]
Effects of HeNe and GaAs lasers on inactivated enzymes arylsulphatases, Na+-K+ ATPase and myosin ATPase
No full textEffects of HeNe and GaAs lasers on inactivated enzymes arylsulphatases, Na+-K+ ATPase and myosin ATPas
effects of chondroitin sulfates with different structures on leukemia-cells - U-937 cell-proliferation and differentiation
No full textChondroitin sulfates extracted and purified by different manufacturers were tested to evaluate their effects on proliferation and differentiation processes of U-937 cells. The different chondroitin sulfates were evaluated for purity, structure and physicochemical properties. The three chondroitin sulfates utilized did not present other contaminant glycosaminoglycans and proteins and had about the same relative molecular mass but different disaccharide patterns and charge density. Chondroitin sulfates with small amounts of disulfated disaccharides and low charge density, at 5 mug/ml concentration, doubled (about + 133%) cell proliferation in comparison to controls. In contrast, chondroitin sulfates with large amounts of disulfated disaccharides and high sulfate to carboxyl ratio were less effective (about + 15%) in stimulating cell proliferation at low concentration. A decrease of U-937 cell proliferation was observed in proportion to the increased amounts of chondroitin sulfate with low sulfate to carboxyl ratio. On the contrary, chondroitin sulfate with large amounts of disulfated disaccharides produced increased cell proliferation depending on concentration. Small amounts (5-10 mug/ml) of chondroitin sulfates with low charge density reduced the differentiative process of U-937 cells. Chondroitin sulfate with large amounts of disulfated disaccharides and high charge density seemed to be able to produce a significant decrease of differentiative processes only at very high concentrations (1000 mug/ml). These contrasting effects of chondroitin sulfates with different disaccharide patterns (and structure) and charge density on a leukemia cell line could help to explain the regulation of proliferative and/or differentiative processes of hemopoietic cells. This is underlined by the changes of types, physicochemical properties and structure of glycosaminoglycans induced by different extracellular factors and agents
Effects of laser on ATPases: reactivation on partially denatured myosin ATPase by GaAs pulsed laser.
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