Table I

Assessment of variability in the quantification of inhibitory site phosphorylation status in the combined population of Cdk1 and Cdk2

Tp-YpT-YpTp-YT-Y
fmol
1) 2-μg eq of Jurkat T cell extract (triplicate measurements)14.613.155.6820.10
16.483.574.8520.61
15.012.825.2518.56
    Average15.363.185.2619.76
    CV (%S.D.)6.4011.857.905.40
2) Same cellular extract as above but independently trypsinized (technical replicate, duplicate measurements)11.343.455.0318.77
(26.16)a(8.36)(4.28)(4.97)
13.283.466.2320.49
(13.59)(8.82)(18.55)(3.72)
3) Independently prepared Jurkat T cell extract (biological replicate, duplicate measurements)11.302.895.4421.88
(26.45)(9.05)(3.45)(10.76)
10.792.724.8018.14
(29.75)(14.51)(8.71)(8.16)
CV (with the inclusion of duplicate measurements from the technical and biological replicates)16.5311.029.576.81
  • a For each measurement carried out as part of the second and third experiments, percentage (%) difference with respect to the mean from the first experiment is given within parentheses in italicized font. Overall from four different biological samples with multiple technical and biological replicates and multiple measurements, we observed CV ranging from 4.5 to 23.8% with most between 12 and 22%.