Western blot analysis of the culture medium and cell lysate for γ387D- and AαBβ-CHO cells. After growth of the cells in the culture dishes to about 70% to 80% confluence, the cells were harvested, and in other dishes, the culture medium was removed (day 0) and aprotinin-containing fresh medium was added. Media were harvested after an additional 1, 3, or 7 days. Cell lysates were subjected to 8% SDS-PAGE under nonreducing conditions (A) or 10% SDS-PAGE under reducing conditions (B). Samples from media harvested after an additional 1, 3, or 7 days (20 μL for γ387D and AαBβ and 10 μL for γ387I) were subjected to 10% SDS-PAGE under reducing conditions (C). Samples from 20-fold concentrated media (γ387D- and AαBβ-CHO cells) harvested after an additional 3 days of culture were subjected to 8% SDS-PAGE under nonreducing conditions (D) or 10% SDS-PAGE under reducing conditions (E-H). The blots were reacted with a polyclonal antibody to fibrinogen (A-E) and anti–Aα- (F), anti–Bβ- (G), or anti–γ-chain–specific (E) antibodies and, after a longer exposure of the nitrocellulose membrane to Hyperfilm-ECL, chemiluminescence was developed. Bars at 340 kDa and 155 kDa, and at 67 kDa, 56 kDa, and 47 kDa, indicate intact fibrinogen, and AαBβγ-complex (A,D), or the normal Aα-, Bβ-, and γ-chains (B-C,E-H). Labeled S, I, D, and αβ are purified plasma fibrinogen, γ387I-, γ387D-, and AαBβ-CHO cell line, respectively. Bands numbered from 1 to 6 in panel D are determined by 2-dimensional analysis (data not shown). 1, AαBβ-complex; 2, AαBβ-complex; 3, Aα-polymer; 4, Bβ-polymer; 5, Aα-polymer; and 6, Aα-monomer.