Determination of the Course and Concentration of a Porosity Gradient

The course and %T range of laboratory-made PA gradient gels can be controlled by densitometry if a coloured dye such as p-nitrophenol is added to the denser acrylamide solution prior to gradient formation. After polymerization, the increase in colour

Figure 7 Horizontal electrophoretic apparatus with cooling plate. 1, Cover lock; 2, gassing stud; 3, high voltage connection of the lid; 4, flexible tube to the cooling plate; 7, with a cooling device (not shown); 5, electrode bar (used in isoelectric focusing); 6, electrode ledge; 8, support for cooling plate. For PA gradient gel electrophoresis the electrode bars are replaced by two buffer vessels (not shown) under the cooling plate and connected to the electrode ledge. The gel is connected to the buffer reservoirs by (paper) wicks (not shown). Reproduced with permission from Rothe (1991).

Figure 7 Horizontal electrophoretic apparatus with cooling plate. 1, Cover lock; 2, gassing stud; 3, high voltage connection of the lid; 4, flexible tube to the cooling plate; 7, with a cooling device (not shown); 5, electrode bar (used in isoelectric focusing); 6, electrode ledge; 8, support for cooling plate. For PA gradient gel electrophoresis the electrode bars are replaced by two buffer vessels (not shown) under the cooling plate and connected to the electrode ledge. The gel is connected to the buffer reservoirs by (paper) wicks (not shown). Reproduced with permission from Rothe (1991).

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Giucose-6-phosphate dehydrogenase

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Giucose-6-phosphate dehydrogenase

intensity from top to bottom of the gel can be used to measure the course of the gradient and its precise concentration in polyacrylamide. For a 1 mm thick gel 15 mg p-nitrophenol may be added to 100 mL of the dense acrylamide solution. After gelation the colour intensity is quantified by densitometry at 405 nm. Whilst the course of the gradient can be seen directly on the densitogram, the %Trange of the gradient can be calculated with the formula:

where Ts (%) is PA concentration of stock solution, E405 is absorbance of p-nitrophenol, Ep is absorbance of empty cassette at 405 nm, c (gL_1) is concentration of p-nitrophenol in stock acrylamide solution (c = 0.150), Mr (g L_1) is mol mass of p-nitrophenol (Mr = 139.1), d (mm) is thickness of gel (e.g. 0.5), E [L(molmm)-1] = molar extinction coefficient of p-nitrophenol at 405 nm (s = 1728) and T (%), as in eqn [1].

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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