SDS-PAGE. Plasma and recombinant fibrinogens were analyzed under nonreducing (6% polyacrylamide gel, A) and reducing (10% polyacrylamide gel, B through D) conditions. A through C were stained with Coomassie blue; D was stained with Schiff reagent. Panels A, B, and D are fibrinogen; C is fibrin; lane 1 samples are plasma protein and lane 2 samples are recombinant protein. Molecular weight markers for the nonreduced gel is indicated at the left and for the reduced gels at the right.