Louisianin A (1) was treated with phosphoryl chloride (POC13) at 120~ 125°C3) to obtain chloro derivative (2) in 86% yield. 2 was reduced by Zn-AcOH at 50°C4) to afford 3 (52% yield) and 4 (35% yield). Furthermore, under the same condition, 3 was dechlorinated to give 4 in 48% yield. Moreover, 4 was oxidized in the treatment of CrO3-pyridine5) to obtain louisianin C (5) in 75% yield. Finally, 5...

Pyruvate, phosphate dikinase from Bacteroides symbiosus catalyzes the conversion of pyruvate, ATP, and Pi to Penolpyruvate, AMP, and PP,. Initial velocity studies by both the forward and reverse reactions in which the three substrates were varied in a constant ratio were found to be in accord with a Tri Uni Uni Ping Pong mechanism. The reaction involves three partial reactions which were invest...

Bacteria have a great influence on the migration behaviour of heavy metals in the environment. Lipopolysaccharides form the main part of the outer membrane of Gram-negative bacteria. We investigated the interaction of the uranyl cation (UO2(2+)) with lipopolysaccharide (LPS) from Pseudomonas aeruginosa by using potentiometric titration and time-resolved laser-induced fluorescence spectroscopy (...

Phosphoryl-transfer reactions are central to biology. These reactions also have some of the slowest nonenzymatic rates and thus require enormous rate accelerations from biological catalysts. Despite the central importance of phosphoryl transfer and the fascinating catalytic challenges it presents, substantial confusion persists about the properties of these reactions. This confusion exists desp...

Diacylglycerol kinase is an integral membrane protein which catalyzes phosphoryl transfer from ATP to diacylglycerol. As the smallest kinase known, it shares no sequence homology with conventional kinases and possesses a distinct trimer structure. Thus far, its catalytic mechanism remains elusive. Using molecular dynamics and quantum mechanics calculations, we investigated the co-factor and the...

Enzymatic activities involved in glucose fermentation of Actinomyces naeslundii were studied with glucose-grown cells from batch cultures. Glucose could be phosphorylated to glucose 6-phosphate by a glucokinase that utilized polyphosphate and GTP instead of ATP as a phosphoryl donor. Glucose 6-phosphate was further metabolized to the end products lactate, formate, acetate, and succinate through...

The high resolution crystal structures of two interacting proteins from the phosphoenolpyruvate:sugar phosphotransferase system, the histidine-containing phosphocarrier protein (HPr) and the IIA domain of glucose permease (IIA(Glc)) from Bacillus subtilis, provide the basis for modeling the transient binary complex formed during the phosphoryl group transfer. The complementarity of the interact...

Different types of natural, commercial and modified asbestos fibres were tested in a highly standardized manner by peritoneal injection into rats and mice in order to assess their carcinogenicity. Differences in mesotheliomatogenic effect were found between the various materials tested. Of particular interest is the finding that treatment of the fibres with phosphorus oxychloride and heating to...