Alkaline phosphatase (EC 3.1.3.1) containing m-flurotyrosine has been prepared from E. coli grown in the presence of m-flurotyrosine. The kinetic properties of the m-fluorotyrosine enzyme measured with p-nitrophenylphosphate at pH 8.0 and dinitrophenylphosphate at pH 5.5 are essentially the same as those of normal alkaline phosphatase. However, the ability of the m-fluorotyrosine protein to ref...

Cytoplasmic pH homeostatic activities of cell wall-defective derivatives of the alkaliphile Bacillus lentus C-125 were assessed using a pH-sensitive fluorescent probe, BCECF. It was shown that the acidic cell wall components took part in maintenance of the cytoplasmic pH neutrality at alkaline pH.

The preparation of a new stable and active form of chymotrypsin is described. The enzyme possesses threonine-147 instead of alanineas the NH&erminal group of the C chain and has been called ai-chymotrypsin. The conformational transition that affects chymotrypsins at alkaline pH was investigated and compared with that of 01and &chymotrypsins by studying the kinetic constants and their pH depende...

A robust and re-usable dipstick-type fluorescent pH sensor for the alkaline pH range was developed by embedding a brightly fluorescent boron-dipyrromethene (BODIPY) dye bearing an acidic phenol moiety into a polyurethane matrix immobilized on a 3D epoxy-functionalized polymer support. The sensor strip has a dynamic working range of pH 10.0-13.1, i.e., operates in strongly basic media where pH g...

Because dietary acid increases renal secretion of endothelin-1 (ET-1) which is synthesized by renal microvascular endothelium, we examined if reduced extracellular pH increases ET-1 secretion by cultured human renal microvascular endothelial cells (RMVECs). Confluent cells were exposed to serum-free media for 24 h, then incubated in either control, acid, or alkaline serum-free media for 12 h. S...

An alkali tolerant Bacillus strain having extracellular serine alkaline protease activity was newly isolated from compost and identified as Bacillus clausii GMBE 22. An alkaline protease (AP22) was 4.66-fold purified in 51.5% yield from Bacillus clausii GMBE 22 by ethanol precipitation and DEAE-cellulose anion exchange chromatography. The purified enzyme was identified as serine protease by LC-...

Our previous report showed gastric mucosal surface pH was determined by alkali secretion at intragastric luminal pH 3 but by acid secretion at intragastric pH 5. Here, we question whether regulation of mucosal surface pH is due to the effect of luminal pH on net acid/base secretions of the whole stomach. Anesthetized rats with a gastric cannula were used, the stomach lumen was perfused with wea...

BACKGROUND The importance of weakly acidic and weakly alkaline reflux in gastro-oesophageal reflux disease (GERD) is gaining recognition. AIM To quantify the proportions of reflux episodes that are acidic (pH <4), weakly acidic (pH 4-7) and weakly alkaline (pH >7) in adult patients with GERD, and to evaluate their correlation with symptoms. METHODS Studies were identified by systematic PubM...

Large numbers of magnetotactic bacteria were discovered in mud and water samples collected from a number of highly alkaline aquatic environments with pH values of ≈ 9.5. These bacteria were helical in morphology and biomineralized chains of bullet-shaped crystals of magnetite and were present in all the highly alkaline sites sampled. Three strains from different sites were isolated and cultured...

Phox2b-expressing glutamatergic neurons of the retrotrapezoid nucleus (RTN) display properties expected of central respiratory chemoreceptors; they are directly activated by CO2/H(+) via an unidentified pH-sensitive background K(+) channel and, in turn, facilitate brainstem networks that control breathing. Here, we used a knock-out mouse model to examine whether TASK-2 (K2P5), an alkaline-activ...