Antithrombin L99F (antithrombin Budapest-III); characterization of purified plasma glycoforms of homozygous patients. (A) SDS-PAGE and silver staining of β-L99F and α-wild type (αWT) glycoforms present in the heparin affinity chromatography fractions eluting at 1M NaCl from plasma of L99F and wild-type homozygous subjects. (B) Isoelectrofocusing of plasma samples. Isoelectrofocusing fractions from control plasma and one of the homozygous Budapest-III (L99F^−/−) collected with an off-gel system were run under reduced SDS conditions and detected by Western blot. The fractions obtained between pI 5.5 and 5.63 mainly contained the β-glycoform of antithrombin.