C4 Protein

Purified human C4 protein

Store at -70°C or below. Avoid freeze/thaw.

Frozen liquid. 10 mM sodium phosphate, 145 mM NaCl, pH 7.3. No preservative, 0.22 µm filtered.

Purified human complement component C4. C4 is one of the proteins unique to the Classical Complement Pathway. The 200 kD C4 protein is made up of three peptide chains linked by disulfide bonds and contains a thioesterbond. When the classical pathway is activated, C1s cleaves C4 to C4a (a weak anaphylatoxin) and C4b. C4b can then bind covalently to a target surface or complex. It can then function as an opsonin or participate as part classical pathway convertase. C4 has been shown to exist as two separate "complotypes" C4A and C4B. These have been shown to have different biological properties.