The regional policy in China is shifting from solely gross domestic product (GDP) orientation to development that is more balanced between economic growth and ecological protection, as well as achieving equality among regions. Using land use maps and the adjusted value coefficients to assess ecosystem service values (ESV) for the 1980s, 1995, 2000, and 2010, we estimated the ESV in Shaanxi Prov...

alpha-1,3-Fucosyltransferase V (FucT V) catalyzes the transfer of 1-fucose from the donor sugar guanosine 5'-diphospho-beta-1-fucose (GDP-Fuc) to an acceptor sugar. A secondary isotope effect on the fucosyltransfer reaction with guanosine 5'-diphospho-[1-2H]-beta-1-fucose (GDP-[1-2H]-Fuc) as the substrate was observed and determined to be Dv = 1.32 +/- 0.13 and DV/K = 1.27 +/- 0.07. Competitive...

The monosaccharide fucose is an important deoxyhexose occurring in plants, fungi and animals. Fucose is mainly found as a component of glycan structures such as Nand O-linked glycans, glycolipids and in cell wall polysaccharides such as fucoidan, xyloglucan, rhamnogalacturonan II. The biosynthesis of these glycan structures is mediated by glycosyltransferases and typically occurs within the end...

In this study, we investigated the biochemical mechanisms of agonist action at the G protein-coupled D2 dopamine receptor expressed in Chinese hamster ovary cells. Stimulation of guanosine 5'-O-(3-[35S]thio)triphosphate ([35S]GTPgammaS) binding by full and partial agonists was determined at different concentrations of [35S]GTPgammaS (0.1 and 10 nM) and in the presence of different concentration...

GDP-d-mannose (GDP-d-Man) is an important intermediate in ascorbic acid (AsA) synthesis, cell wall synthesis, protein N-glycosylation, and glycosylphosphatidylinositol-anchoring in plants. Thus, the modulation of intracellular levels of GDP-d-Man could be important for maintaining various cellular processes. Here an Arabidopsis GDP-d-Man pyrophosphohydrolase, AtNUDX9 (AtNUDT9; At3g46200), which...

Purified guanine nucleotide-binding regulatory proteins, as either the oligomers or the isolated nucleotide-binding alpha subunits, display anomalous kinetics of nucleotide binding. This is due to the presence of tightly bound GDP in these preparations. The dissociation of bound GDP is the rate-limiting step for nucleotide binding. GDP can be removed by chromatography in the presence of 1 M (NH...

Congenital Disorders of Glycosylation (CDG) are human deficiencies in glycoprotein biosynthesis. Previous studies showed that 1 mM mannose corrects defective protein N-glycosylation in cultured fibroblasts from some CDG patients. We hypothesized that these CDG cells have limited GDP-mannose (GDP-Man) and that exogenous mannose increases the GDP-Man levels. Using a well established method to mea...

The plant VTC2 gene encodes GDP-L-galactose phosphorylase, a rate-limiting enzyme in plant vitamin C biosynthesis. Genes encoding apparent orthologs of VTC2 exist in both mammals, which produce vitamin C by a distinct metabolic pathway, and in the nematode worm Caenorhabditis elegans where vitamin C biosynthesis has not been demonstrated. We have now expressed cDNAs of the human and worm VTC2 h...

Polypeptide chain initiation in mammalian systems is regulated at the level of the guanine nucleotide exchange factor (GEF). This multisubunit protein catalyzes the exchange of GDP bound to eukaryotic initiation factor 2 (eIF-2) for GTP. Although various models have been proposed for its mode of action, the exact sequence of events involved in nucleotide exchange is still uncertain. We have stu...