Beta-gal Assay Experimenter: . Date: .

Comments: .

1. Spin down cells, resuspend them in Z Buffer. 5. Add 200 ml ONPG to start reaction.

2. Dilute (vol. #1) of cells in 1000 ml water, 6. Add 500 ml 1M Na₂CO₃ to stop reaction.

measure OD₆₀₀ (should be less than 0.4) 7. Spin down the debris, measure OD₄₂₀.

3. Dilute (vol. #2) ml of cells in 1000 ml Z Buffer

+ 4 ml 1% SDS + 25 ml CHCl₃ Miller Units =

4. Vortex 10 seconds, then incubate at 28°C for 1000 x vol. #1 x OD₄₂₀ .

5 minutes. vol. #2 OD₆₀₀ x reaction time

	Strain	Vol. #1	OD600	Vol. #2	ONPG time added	Na2CO3 time added	Reaction time(min)	OD420	Miller Units
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40