反应 #353226

反应方程式

DTT

potassium phosphate

sodium cholate

PMSF

EDTA

→

CHOLESTEROL

溶剂

glycerol

反应条件

后处理

1. 1
   workup.WAITAfter induction, the cultures were harvested by centrifugation at 5,000 rpm for ten minutes at 4° C
2. 2
   其他The supernatant was collected
3. 3
   其他after spinning down the total lysate at 100,000×g for one (1) hour at 4° C
4. 4
   其他stored on ice overnight
5. 5
   workup.ADDITIONafter the addition of 100 units of DNaseI
6. 6
   洗涤This column was washed
7. 7
   洗涤eluted with the same buffer
8. 8
   其他The eluted fractions were dialyzed against buffer B (10 mM potassium phosphate, pH 7.4, 0.2% sodium cholate, 0.2% Emulgen 911, 0.1 mM EDTA, 0.05 mM DTT, 0.5 mM phenyl methyl sufonyl fluoride (PMSF))
9. 9
   洗涤This column was then washed with 200 ml of 10 mM potassium phosphate buffer
10. 10
    洗涤with 150 ml of 50 mM potassium phosphate buffer and then eluted with 300 ml of 100 mM potassium phosphate buffer
11. 11
    其他dialyzed against 10 mM potassium phosphate buffer, pH 7.4, 20% glycerol, 0.1 mM EDTA, 0.1 mM DTT, 0.5 mM PMSF and 0.2% Emulgen 911 (buffer C)
12. 12
    洗涤eluted with buffer C
13. 13
    workup.ADDITIONcontaining 360 mM potassium phosphate

实验过程

After induction, the cultures were harvested by centrifugation at 5,000 rpm for ten minutes at 4° C. The cells were then resuspended in 1/100 volume of buffer A (100 mM potassium phosphate, pH 7.4, 0.5% sodium cholate, 20% glycerol, 0.1 mM EDTA, 0.1 mM DTT and 0.5 mM PMSF). The cells were then lysed in buffer A with 200 μg/ml lysozyme. The supernatant was collected after spinning down the total lysate at 100,000×g for one (1) hour at 4° C. The pellet was resuspended thoroughly in the same buffer and centrifuged again. Both supernatants were combined and stored on ice overnight after the addition of 100 units of DNaseI. The clear lysate was then applied to an Octylamino Sepharose 4B column (2.6×15 cm). This column was washed and eluted with the same buffer. The eluted fractions were dialyzed against buffer B (10 mM potassium phosphate, pH 7.4, 0.2% sodium cholate, 0.2% Emulgen 911, 0.1 mM EDTA, 0.05 mM DTT, 0.5 mM phenyl methyl sufonyl fluoride (PMSF)), applied to a hydroxyapatite column (2.4×7 cm) and equilibrated with the same buffer. This column was then washed with 200 ml of 10 mM potassium phosphate buffer, then with 150 ml of 50 mM potassium phosphate buffer and then eluted with 300 ml of 100 mM potassium phosphate buffer. These three buffers also contained 20% glycerol, 0.3% sodium cholate, 0.05 mM EDTA, 0.1 mM DTT and 0.5 mM PMSF. The purified sample was brought to 0.2% Emulgen 911 and then dialyzed against 10 mM potassium phosphate buffer, pH 7.4, 20% glycerol, 0.1 mM EDTA, 0.1 mM DTT, 0.5 mM PMSF and 0.2% Emulgen 911 (buffer C). The sample was then applied to a second hydroxylapatite column (0.5×3.0 cm) equilibrated with buffer C and eluted with buffer C but containing 360 mM potassium phosphate. At this stage, the purity of the human cholesterol 7α-hydroxylase was confirmed by SDS-polyacrylamide gel electrophoresis.

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