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Isolation of two forms of decay-accelerating factor (DAF) from human urine
Y Nakano1, Y Sugita, Y Ishikawa
1Department of Physiological Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
Abstract:
Decay-accelerating factor (DAF) was purified from human pooled urine by conventional techniques. The urine DAF was separated into two peaks, pool I and pool II, by gel chromatography. DAF-U1 was isolated from pool I by hydrophobic chromatography, and DAF-U2 from pool II by anti-DAF IgG column. The specific activities of DAF-U1 and DAF-U2 to decay membrane-phase C5 convertase were about 3% and 70% of membrane form DAF, respectively. However, both urine DAFs revealed a similar activity to each other and slightly higher activity than that of membrane form DAF in decay-accelerating fluid-phase C3 convertase of the alternative pathway.