Figure 11. SDS-PAGE profiles of proteins bound to serum granulations and protein identification.

(A) Serum granulations (pellets) were prepared exactly as in Fig. 1, from either untreated FBS (referred as “None”) or through the addition of the indicated amounts of CaCl₂ (“Calcium”) and/or Na₂HPO₄ (“Phosphate”) to FBS. The indicated sequence of the lanes depicted in the heading matches exactly with the sequence of wells seen in Fig. 1. No protein band was found in the pellet of untreated FBS (lane 1), whereas the other lanes showed dose-dependence with respect to the precipitating reagents used. The white marks represent the positions of the bands excised for identification by MALDI-TOF mass fingerprint analysis whereas the identified proteins are shown on the right. While bovine serum albumin (BSA) and apolipoprotein A1 (b Apo-A1) were the only proteins identified in their respective positions, other proteins besides bovine fetuin-A (BSF) were also identified in the 52–65 kDa range (see the text for details). (B) This HS pellet was obtained with 30 mM CaCl₂ and processed exactly as done with the FBS pellets. Abbreviations used: HSA, human serum albumin; HSF, human serum fetuin-A; and h Apo-A1, human apolipoprotein A1.