Isolation of the First Component of Complement (C1) from Carp Serum

The first component of complement (C1) was isolated from carp serum by a 6-step purification procedure: 1) affinity chromatography (I) on Blue Cellulofine, 2) QAE-Sephadex A-50 chromatography, 3) gel filtration on Sepharose CL-6B, 4) Blue Cellulofine chromatography (II), 5) DEAE-Toyopearl 650 m chromatography (I), and 6) DEAE-Toyopearl 650M chromatography (II). The final recovery of C1 hemolytic activity was 18%, representing a 788-fold purification. The purity of the isolated carp C1 was established by gel filtration on Sepharose CL-6B and by immunoelectrophoresis against anti-whole carp serum (rabbit). The molecular weight of carp C1 was estimated to be 1,020,000. The hemolytic activity of carp C1 was inhibited by EDTA treatment, but this inhibition was overcome by dialysis against a Ca²⁺-containing buffer. The hemolytic activity of carp C1 was destroyed by heating (50°C, 10 min) or incubation with carrageenan, but was retained when incubated with ammonia, hydrazine or zymosan. This indicates that carp C1 resembles mammalian C1 in chemical properties.