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The DALT Blotting Kit
Hoefer DALT System
38
Amersham Biosciences
Connecting the Power Supply
If using a power supply that can be set to either constant current or constant voltage
mode, we recommend that it be set to operate in constant current mode. Buffer
conductivity increases with temperature. During blotting in an uncooled chamber at
constant voltage, Joule heating and rising conductivity may result in dangerous
overheating. If a constant voltage power supply must be used, monitor and adjust the
voltage to maintain a current at 1000 mA, or less, and voltage should not exceed 100 V.
1. Close the plastic lid on the chamber. The cassettes are labeled to match the leads in
the lid.
To transfer toward the anode, position the lid so that the (+) side of the cassette
faces the anode (+), or red lead, and the (–) side of the cassette faces the cathode (–),
or black lead.
2. Connect the leads to your power supply.
3. Set the power supply. See Table 1 for typical transfer parameters for proteins.
Constant current mode is recommended. If constant voltage mode is selected,
carefully monitor the current. Increased current increases Joule heating. If the
current exceeds 1.0 A, decrease the voltage.
I
MPORTANT
The plastics used in the DALT unit may warp at high temperatures.
Because electrophoretic transfers are performed at high currents,
considerable heat is generated during a run. Do not allow the buffer
temperature to exceed approximately 40 °C.
If you are planning to do a second transfer or set of transfers in the same buffer, be
sure to maintain constant temperature or to cool the buffer to room temperature
between the two runs. Do not allow the buffer to overheat and damage the unit.
4. Set the timer.
Most transfers are complete with 5 hours, but larger molecules or thicker gels may
require longer transfer times. Determine the optimum transfer time for your system
empirically.
N
OTE
For overnight transfers, set the current at 400 mA with active cooling.
Table 1.
Typical Transfer
Parameters for Proteins
Buffer*
Towbin*
Current (A)
up to 1
Voltage (V)
approx. 70
Transfer time
approx. 5 hours
Coolant temperature
10 °C
*Empirically determine the parameters for your sample and buffer system.
Содержание Hoefer DALT
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