Xylene cylanol

The reaction may be quenched by the addition of ammonium chloride to a final concentration of 50 mM. Some protocols also include at this point the addition of 0.1 percent xylene cylanol and 5 percent glycerol as a photon absorber and protein stabilizer, respectively. React for a further 2 hours to stop the reaction by blocking remaining isothiocyanate groups. 

Provided. 0.2% phenolphthalein in 90% ethanol, either modified methyl orange (mixture of methyl orange and xylene cylanole FF available from East-m Kodak Co.) or 0.1% bromcresol green in 0.001 M NaOH, and either primary standard Na2C03 or standardized 0.1 M NaOH. 

After overnight incubation at room temperature, remove excess free glutaraldehyde by gel filtration. To do this, use a gel matrix with an exclusion limit of 20,000"C50,000 for globular proteins. Use medium-sized beads (approx 100 pm in diameter). Prepare a column with 5 mL of bead volume according to the manufacturer s instructions. To make the column easier to load and run, first add 20 pL of glycerol and 20 pL of 1% xylene cylanol. The column should be prerun with a minimum of 10 column vol of 0.15 MNaCl. Allow the column to run until the buffer level drops just below the top of the bed resin. Stop the flow of the column. Carefully load the column with the glutaraldehyde-treated HRP. Release the flow and allow the HRP to run into the column. Just as the level of the HRP solution drops below the top of the column, carefully add 0.15 MNaCl. Run the column with 0.15 MNaCl. Pool the fractions that look brown. These contain the active enzyme. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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