Independent method validations
and complex applications of SP4
cleanup for proteomics. The SP4 protocol was provided to three collaborators
and applied to several sample types to compare SP4 with SP3. (A) Lab
1 performed SP3 with either SpeedBeads carboxylate or ReSyn HILIC
magnetic beads compared with overnight acetone (ACT(O/N)) precipitation
and SP4-GB for 1, 10, and 250 μg preparations of Jurkat human
immortalized T cell lysate (n = 3). †n = 2; see Supporting Methods. (B) Acetone precipitation and SP4 were compared for 250 μg
HEK293 lysate digested with trypsin +/− Lys-C. (C) Lab 2 processed
25 μg of HEK293 lysate for SP3, SP4-BF, and SP4-GB protocols.
(D) Lab 3 processed two independent n = 5 comparisons
of SP3 and SP4-GB using 50 μg of E14 murine embryonic stem cell
lysate. (E) SP3 and SP4 preparations of more complex lysates/homogenates
derived from whole organs, organisms, and formalin-fixed paraffin-embedded
(FFPE) tissue. Bar charts present median and standard deviation, with
significance assessed by ANOVA (A, C) and t-test
(B, D, E). Protein coefficients of variance distributions represented
by violin plot (thick line–median, thin lines–quartiles).
*p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, and ns–not
significant.