6-Phosphofructo-2-kinase and D-fructose-2,6-bisphosphatase activities in mung bean seedlings

6-Phosphofructo-2-kinase (ATP: D-fructose-6-phosphate-2-phosphotransferase) and D-fructose-2,6-bisphosphatase activities have been found in extracts prepared from etiolated mung bean seedlings. The activity of 6-phosphofructo-2-kinase exhibits a sigmoidal shape in response to changes in concentrations of both substrates, D-fructose 6-phosphate and ATP (S_0.5 values of 1.8 and 1.2 mM, respectively). Inorganic orthophosphate (P_i) has a strong stimulating effect on the 2-kinase activity (A_0.5 at about 2 mM), moderately increasing the V_max and modifying the response into hyperbolic curves with K_m values of 0.4 and 0.2 mM for fructose 6-phosphate and ATP, respectively. 3-Phosphoglycerate (I_0.5 about 0.15 mM) partially inhibited the kinase activity by counteracting the P_i activation. In contrast, the activity of D-fructose-2,6-bisphosphatase (K_m 0.38 mM) is strongly inhibited by P_i (I_0.5 0.8 mM) lowering its affinity to fructose-2,6-P₂ (K_m 1.4 mM). 3-Phosphoglycerate activites the enzyme (A_0.5 at about 0.3 mM) without causing a significant change in its K_m for fructose-2,6-P₂. The activities of both of these enzymes in relationship to the metabolic role of D-fructose 2,6-bisphosphate in the germinating seed is discussed.     

The first vitamin B6 zinc complex, pyridoxinato-zinc acetate: A 1D coordination polymer with polar packing through strong inter-chain hydrogen bonding

The biologically important pyridoxinato(1−) ligand (anionic vitamin B₆) shows the rare phenolate-hydroxymethyl chelation plus bridging mode through the pyridine-nitrogen atom towards zinc(II) to give the one-dimensional (1D) coordination polymer {(acetato-κO)-aqua-μ-[2-methyl-3-oxy-4,5-di(hydroxymethyl)pyridine-κN:O,O′]zinc(II)}·monohydrate with polar packing of adjacent chains along the polar c axis (in space group Pc) through strong inter-chain hydrogen bonding.     

Iridoid glucosides in fouquieriaceae

From three Fouquieria sp. 12 iridoid glucosides were isolated and identified. Eight of these were structurally related to galioside (monotropein methylester), while four were hydroxy substitution products of deoxyloganin. In three cases the glucoside occurred together with the corresponding 10-O-acetate.     

Clinical adaptation of a high-performance liquid chromatographic method for the assay of pyridoxal 5′-phosphate in human plasma

Vitamin B6, measured as pyridoxal 5′-phosphate (PLP), is a co-enzyme in the transsulfuration pathway of homocysteine metabolism. Since depletion of PLP has been suggested as an independent risk factor for coronary artery disease, PLP is frequently measured to guide patient care. By a change and utilization of an Aquasil C18 column and the addition of an acetonitrile clean-up gradient to the potassium phosphate, with sodium perchlorate and bisulfite buffer between samples we report the modification of a previously described method for analysis of PLP. The result is a more practical, efficient, reliable and robust method for daily clinical use. We also determined and report that it is critical to protect freshly prepared standard PLP samples from light exposure during assay preparation.     

Microtubules promote the non-cell autonomous action of microRNAs by inhibiting their cytoplasmic loading onto ARGONAUTE1 in Arabidopsis

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A world of cytochrome P450s

The world we live in is a biosphere influenced by all organisms who inhabit it. It is also an ecology of genes, with some having rather startling effects. The premise put forth in this issue is cytochrome P450 is a significant player in the world around us. Life and the Earth itself would be visibly different and diminished without cytochrome P450s. The contributions to this issue range from evolution on the billion year scale to the colour of roses, from Darwin to Rachel Carson; all as seen through the lens of cytochrome P450.     

Prediction of the halothane (Hal) genotypes of pigs by deducing Hal, Phi, Po2, Pgd haplotypes of parents and offspring: results from a large-scale practice in Swedish breeds

Results from a large-scale study, comprising 75 different breeding herds, are reported on predicting the halothane ( Hal ) genotypes of individual pigs by making use of the known close linkage between Hal and three C blood marker loci ( Phi, Po2, Pgd ). The parents haplotypes (involving Hal and marker loci) were determined from the HAL phenotypes (halothane test results) and marker loci phenotypes of their offspring in the first one or two litters studied. In subsequent litters of the Hal -marker loci haplotyped parents, the offspring's expected Hal genotypes could be predicted on the basis of the marker loci haplotypes inherited by them. By comparing the expected and observed HAL phenotypes of offspring in subsequent litters, the predicted Hal genotype was found to be correct in 90–95 % of the 4000 offspring (from Nn × Nn and Nn × nn matings) of Swedish Landrace and Yorkshire breeds studied.
The order of the three marker loci was confirmed as Phi-Po2-Pgd but the position of Hal with regards to Phi could not be resolved. The recombination frequencies between the most distant loci in this region, viz. Hal-Pgd and Phi-Pgd , were estimated to be 3–4.5 % and 4–6 % , respectively. The easy and rapid electrophoretic techniques described in the study to phenotype PHI, PO2, PGD, also allowed phe-notyping of six other polymorphic protein systems on the same gels. Thus Hal genotyping and effective parentage control can be conducted simultaneously.