The proposal that microtubule dynamic instability results from stabilization of microtubule ends by tubulin-GDP-Pi subunits (where Pi is inorganic phosphate) [Melki et al. (1996) Biochemistry 35, 12038] was based on studies of GTP hydrolysis and microtubule assembly that showed that tubulin-GDP-Pi subunits can transiently accumulate at microtubule ends. There is no direct evidence that GDP-Pi-s...

Thyroid fucokinase is responsive to a number of metabolites which might serve in a regulatory capacity. In addition to inhibition by ADP and stimulation by GMP, fucokinase responds selectively to a series of nucleotide sugars. Of those studied, only guanine nucleotide sugars moderate the activity of the enzyme. GDP-a-D-mannose, GDP-a-D-glucose, GDP-cY-D-rhamnose, and GDP-cu-L-rhamnose all stimu...

A eukaryotic initiation factor 2 (eIF-2)-ancillary protein factor Co-eIF-2 promotes displacement of GDP from eIF-2 X GDP and facilitates ternary complex (Met-tRNAf X eIF-2 X GTP) formation in the presence of Mg2+. Heme-regulated protein synthesis inhibitor, HRI, phosphorylates the alpha-subunit of eIF-2 and thus inhibits ternary complex formation as Co-eIF-2 does not displace GDP from eIF-2 alp...

The first committed enzyme in GDP-L-fucose formation from GDP-D-mannose is GDP-D-mannose 4,6-dehydratase, which forms GDP-4-keto-6-deoxy-D-mannose. The uncertain enzymatic steps beyond this point were examined in this study. Assays were developed for the epimerase and reductase activities which the putative pathway would predict. A protein was isolated exhibiting homogeneity by several criteria...

GDP (Gross domestic product) and per capita GDP data of six GCC (Gulf Cooperation Council) countries were collected and analysed by randomized complete bock design and pair-wise multiple comparison. It is observed that GDP of Saudi Arabia is significantly higher than that of all other GCC countries. The GDP of Bahrain, Qatar, Oman and Kuwait are similar. The GDP of UAE is significantly higher t...