Western blot analysis of the factor XII Tenri family. Factor XII in plasmas of the proband (lane 1), his father (lane 2), mother (lane 3), sister (lane 4), and brother (lane 5) were immunoprecipitated by anti-factor XII antibody. After heat dissociation, immunoprecipitates were electrophoresed on 8% SDS-polyacrylamide gels under nonreducing (A and B) or reducing (C) conditions. Electrophoresed proteins were transferred to polyvinylidene difluoride membranes and then blotted by the biotinylated anti-factor XII antibody followed by avidin-peroxidase. (B) is the overexposure of the high molecular mass region of (A). The sample in lane 6 in (A) was the same as in lane 1, but was blotted by the biotinylated anti-₁–microglobulin antibody.