Sucrose density gradients

Volumes and concentrations for log-linear* sucrose gradients

Calculations of Barbara-Ellen Jackson, Andrew O. Jackson and Myron K. Brakke as described in Analytical Biochemistry 38, 56-64 (1970)

For SW 56 (60) Rotor (4.4ml gradients for 7/16 x 2 3/8 inch cellulose nitrate tubes using 0.2ml samplea)
Pb 1.3
6oC
Pb 1.3
14oC
Pb 1.5
6oC
Pb 1.5
14oC
ml
mg/ml
ml
mg/ml
ml
mg/ml
ml
mg/ml
0.17
0
0.33
0
0.29
0
0.29
0
0.48
80
0.42
80
0.42
80
0.44
80
0.75
160
0.77
160
0.63
160
0.67
160
1.03
210
0.99
210
0.91
210
0.91
210
1.35
260
1.27
260
1.41
260
1.41
270
0.62
300
0.62
300
0.74
300
0.68
300



For SW 56 (60) Rotor (3.9ml gradients for 7/16 x 2 3/8 inch polyallomar tubes using 0.2ml samplea)
Pb 1.3
6oC
Pb 1.3
14oC
Pb 1.5
6oC
Pb 1.5
14oC
ml
mg/ml
ml
mg/ml
ml
mg/ml
ml
mg/ml
0.19
0
0.34
0
0.32
0
0.29
0
0.43
80
0.37
80
0.37
80
0.42
80
0.68
160
0.70
160
0.57
160
0.60
160
0.90
210
0.86
210
0.81
210
0.81
210
1.20
260
1.13
260
1.24
260
1.24
260
0.50
300
0.50
300
0.59
300
0.55
300

* For these gradients log of depth is a linear function of log of sedimentation coefficient, simplifying estimation of sedimentation coefficients. Layered gradients (dilute phosphate buffer) were stored at 2oC for 15-16 hours. After layering samples, the centrifuge rotor was held at low speed until temperature stabilized. See original paper for further details.
a Remove a volume equal to sample size from the top of the gradient shortly before floating samples on the gradients.
b Pb is the buoyant density of the particle in sucrose and the temperature is that at which the gradient is centrifuged. Pb=1.3 is usually used for viruses and Pb=1.5 for RNA centrifugation