Aromatic interactions are well-known players in molecular recognition but their catalytic role in biological systems is less documented. Here, we report that a conserved aromatic stacking interaction between dUTPase and its nucleotide substrate largely contributes to the stabilization of the associative type transition state of the nucleotide hydrolysis reaction. The effect of the aromatic stac...

The demonstration that enolpyruvate-P plus n-erythrose 4-phosphate is converted enzymically to shikimic acid led to the suggestion (1) that the first intermediate in this process was 3deoxy-n-or&in&heptulosonic acid ‘I-phosphate (Compound V, Pig. 1). It was postulated that the newly formed hydroxyl group on C-4 had the stereochemistry shown in Compound V since it would then correspond to that o...

M\ithough inannolheptulose andI perseitol have i)een known as major constituents of avocadlo sugars for matin years (14) no mlechanismi ftor the synthesis or accumulation of these seven carbon sugars has been dlemonstrate(l. Recently miianniolheptulose has been foun(l to be miiore wi(lely distributed than previously b)elievel, having been found in leaves of figs (4) andi alfalfa (15)). Olther l...

The present work examined the effects of dipentaerythritol penta-acrylate phosphate (PENTA) as an alternative phosphate ester monomer for bonding of methacrylate-based resins to yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and further investigated the potential bonding mechanism involved. Shear bond strength testing was performed to evaluate the efficacy of experimental PENTA-cont...

FR901483, a novel immunosuppressant, has been isolated from the fermentation broth of Cladobotryum sp. No. 11231. The molecular formula of FR901483 has been determined as C20H31N2O6P. FR901483 exerts a potent immunosuppressive activity in vitro and significantly prolongs graft survival time in the rat skin allograft model. This compound has an intriguing tricyclic structure possessing a phospha...

Enzyme sensor for organophosphorus insecticides organophosphorus hydrolase in a polymer membrane on a pH sensor is used to catalyse the hydrolysis of compounds with phoshate ester functionality. The detected [H+] change is proportional to the concentration of the phosphate ester insecticide. This is a good example of the use of an enzyme to give selectivity to a specific class of compounds. Unf...

1-Alkyl-sn-glycero-3-phosphate:acyl-CoA acyltransferase activity was found in six rat tissues: heart, spleen, brain, kidney, liver, and lung. The enzyme in rat brain showed highest specific activity in the microsomal fraction and its properties were studied in detail. Triton X-100 and bovine serum albumin were found to stimulate the activity of the enzyme. It was found that Triton X-100 affects...

Chlorophyll is the most abundant photosynthetic pigment in higher plants. During senescence, chlorophyll is hydrolyzed, resulting in the release of free phytol and chlorophyllide. Although the degradation of chlorophyllide has been studied in depth, the metabolic fate of phytol in plants is less clear. Here, we provide evidence that phytol can be incorporated into chlorophyll, tocopherol, and l...

Cell walls were isolated from cells of Bacillus subtilis strain Marburg during synchronous outgrowth of spores, during the two synchronous cell divisions which followed, and at various times during exponential and early stationary growth. The amounts of teichoic acid and peptidoglycan components were determined in each cell wall preparation. The peptidoglycan is composed of hexosamine, alanine,...

Preparation of an agarose derivative (MPE-agarose) containing a maleimido group which is attached to agarose via a cleavable phenyl ester linkage is described. MPE-agarose was shown to react with the thiol groups in glutathione, bovine serum albumin, bovine hemoglobin, and yeast and rabbit muscle glyceraldehyde 3-phosphate dehydrogenase. Treatment of the resulting agarose-linked compounds for 1...