PH pen

This luminous brittle star has been briefly studied recently (Mallefet and Shimomura, 2004, unpublished). The animal contained a high level of coelenterazine luciferase activity (4 x 1012 photons s-1g 1), which is comparable to those in the luminous antho-zoans such as the sea pansy Renilla and sea pen Ptilosarcus (Shimomura and Johnson, 1979b). There is no evidence for the presence of a photoprotein in this brittle star. Thus, the luminescence system of Amphiura filiformis is considered to be a coelenterazine-luciferase system, differing from that of Ophiopsila californica. The luciferase has a molecular weight of 23,000 on the basis of gel filtration on Superdex 200 Prep, and catalyzes the luminescence reaction of coelenterazine in the presence of oxygen the light emission (A.max 475 nm) is optimum at pH 7.2. 

Perchlor-styrol kann elektrolytisch in Methanol/l,2-Dimethoxy-athan (1 1) zu (Pen-tachlor-phenyl)-acetylen dechloriert werden. Daneben treten, je nach pH und Elektro-denmaterial, verschiedene Nebenprodukte in wechselnden Ausbeuten auf2 ... 

As an example the deactivation of immobilised Pen G acylase, which catalyses the reaction of Pen G to 6-Aminopenicillanic acid and Phenylacetic acid, was studied. This enzyme was covalently bound on an ion-exchanger and cross-linked by glutaric aldehyde. To maintain a high reaction velocity, a neutral pH value (removal of Phenylacetic acid) and therefore the supply of NaOH and stirring for distribution of the base are required. 

Two different approaches have been used to determine phenols without derivatization. In the first, the corresponding oxalate esters were synthesized in the traditional way (i.e., using oxalyl chloride and triethylamine) [111, 112]. Pen-tachlorophenol, 1-naphthol, bromofenoxim, bromoxynil, and /t-cyanophenol were treated this way, after which the POCL resulting from their reaction was measured in a static system. The second approach exploits the oxidation reaction between imidazole and hydroxyl compounds at an alkaline pH, where hydrogen peroxide is formed [113]. Polyphenols, e.g., pyrogallol, pyrocatechol, and dopa-... 

Following deparaffination, the sections are treated with 0.05 M TBS, pH 7.6, for 5 min. Dry the slides with paper towels as close to the sectioned material as possible encircle the sectioned material with a DAKO pen (code no. S2002). 

The characteristic shape of the anodic voltammogram of a Si electrode in aqueous fluoride media, as shown for example in Fig. 3. Id, is surprisingly stable against changes in fluoride concentration (cF) or pH. When the potential of a p-type Si electrode is swept anodic of OCP a steep current rise near 0 V is observed, followed by a sharp peak (Jj) and a narrow plateau (J2). Then a second broad maximum (Ji) is found around a positive bias of 1.5-2.5 V, followed by a broad plateau (J4) extending over several volts, as shown in Fig. 4.7. When electrode rotation is used, these curves are pen-reproducible for a given solution. The hysteresis of the curves approaches zero for slow sweeps [Ch3]. 

A 200 mM phosphate-buffered solution, pH 6.9 (100 mL), containing 3-allyl-2,4-pen-tanedione (700 mg, 50 mmol), glucose (2.16 g, 120 mmol), NADPH (45 mg), glucose dehydrogenase (50 mg) and KRED-108 (70 mg) was stirred at room temperature for 24 h, until GC analysis of crude extracts showed complete reaction. Periodically, the pH was readjusted to 6.9 with NaOH (2m). 

In contrast to the R-preference displayed by CALB, quite impressive S-preference toward several 1-aryl-l-ethanols can be achieved by using a protease, the commercially available subtilisin Carlsberg, as catalyst, and isopropenyl pen-tanoate as the acyl donor in THF in the presence of sodium carbonate [74]. To achieve a successful resolution, the protease has to be treated with a mixture of two surfactants, octyl-P-D-glycopyranoside and Brij 56 [the monocetyl ether of polyoxyethylene (10)], 4/1/1 by weight, at pH 7.2, and then lyophilized before use. 

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