Figure 4.

2DE of two different sets of proteins in sRB (A, C) and oRB (B, D). 50 μg of total Xenopus egg extract (A, B) or 25 μg of protein eluted from mitotic chromosomes assembled for 30 min in mitotic Xenopus egg extract (C, D) were dissolved in sRB (8 M urea, 4% CHAPS, 0.5% ampholytes, 20 mM DTT) and oRB (7 M urea, 2 M thiourea, 1.2% CHAPS, 0.4% ASB14, 0.25% ampholytes, 43 mM DTT, 30 mM Tris) and separated as described in Materials and Methods. Spots detected: (A) 425, (B) 659, (C) 112, (D) 350.