Ishizaki E, Mori Y, Koyama J
J Biochem. 1977 Oct;82(4):1155-60. doi: 10.1093/oxfordjournals.jbchem.a131788.
C1 inactivator (C1 INA) was highly purified from rabbit serum. C1 INA thus purified was a single polypeptide chain with a molecular weight of 105,000 or 140,000, as estimated by SDS-polyacrylamide gel electrophoresis or gel filtration on Sephadex G-200, respectively. It inhibited rabbit and also human C1, when the C1 activities were measured in terms of hydrolyses of acetylglycyl-L-lysine methylester, N-alpha-acetyl-L-arginine methylester and N-alpha-acetyl-L-tyrosine ethylester. These properties showed that rabbit C1 INA bears a marked structural similarity to human C1 INA. Furthermore, rabbit C1 INA was capable of inhibiting similarly both rabbit C1s and its active fragment lacking a half of the H chain of C1s, indicating that deletion of a half of the H chain did not affect the susceptibility of C1s to the inhibitory activity of C1 INA.
C1灭活剂（C1 INA）从兔血清中高度纯化。通过SDS-聚丙烯酰胺凝胶电泳或在Sephadex G-200上进行凝胶过滤分别估计，如此纯化的C1 INA是一条单多肽链，分子量分别为105,000或140,000。当根据乙酰甘氨酰-L-赖氨酸甲酯、N-α-乙酰-L-精氨酸甲酯和N-α-乙酰-L-酪氨酸乙酯的水解来测量C1活性时，它抑制兔C1以及人C1。这些特性表明兔C1 INA与人类C1 INA具有显著的结构相似性。此外，兔C1 INA能够同样抑制兔C1s及其缺少C1s H链一半的活性片段，这表明H链一半的缺失并不影响C1s对C1 INA抑制活性的敏感性。
