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Hari G. Garg Hicham Mrabat Craig Freeman Fuming Zhang Charles A. Hales 《Carbohydrate research》2010,345(9):1084-1087
Heparin (HP) inhibits the proliferation of bovine pulmonary artery smooth muscle cells (BPASMC’s), among other cell types in vitro. In order to develop a potential therapeutic agent to reverse vascular remodeling, we are involved in deciphering the relationship between the native HP structure and its antiproliferative potency. We have previously reported the influence of the molecular size and the effects of various O-sulfo and N-acetyl groups of HP on growth-inhibitory activity. In this study, to understand the influence of carboxyl groups in the HP structure required for endogenous activity, a chemically modified derivative of native HP was prepared by converting the carboxyl groups of hexuronic acid residues in HP to primary hydroxyl groups. This modification procedure involves the treatment of HP with N-(3-dimethylaminopropyl)-N-ethylcarbodiimide followed by reduction with NaBH4 to yield carboxyl-reduced heparin (CR-HP). When compared to the antiproliferative potency of native HP on cultured BPASMC’s at three dose levels (1, 10, and 100 μg/mL), the CR-HP showed significantly less potency at all the doses. These results suggest that hexuronic acid residues in both major and variable sequences in HP are essential for the antiproliferative properties of native HP. 相似文献
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The influence of wilting on the levels of free proline, soluble proteins, reducing sugars, starch and on the activities of
nitrate reductase, invertase, amylase and pyrophosphatases have been studied in the leaf tissue of five cultivars of pearl
millet at their vegetative stage under pot culture conditions. The metabolic changes could not be correlated with the yield
behaviour of the cultivars under a drought condition in the field. 相似文献
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Y.S. Chauhan V.S. Rathore G.K. Garg Aruna Bhargava 《Biochemical and biophysical research communications》1978,83(4):1237-1245
An enzyme activity which brings about a rapid indole disappearance has been detected in cell free extracts of maize ( L.) leaves. The indole utilization by this enzyme system is not dependent on L-serine and pyridoxal phosphate. It does not result in incorporation of (5-3H) indole or (1-14C) serine into tryptophan. There was no net tryptophan synthesis concomittant with indole disappearance. The enzyme activity is strongly inhibited by dithionite and diethyl-dithiocarbamate. The inhibition by the latter could be specifically removed by Cu2+. The activity of dialyzed enzyme could be restored by addition of Cu2+ and FAD. The products of indole oxidation were characterized as anthranilic acid and anthranil (2,1-benzisooxazole). The activity of the indole oxidizing system was 2 to 3 times higher in normal maize varieties (Ganga-2 and Ganga-5) than in Opaque-2. 相似文献