Product Description

Natural human C4a is prepared by cleavage of human C4 protein by human C1s. It is produced during activation of both the classical and lectin pathways of complement.C4a is a member of the anaphylatoxin family of three proteins (C3a, C4a and C5a) produced by the activation of complement (Hugli, T.E. et al. (1981)).It is an unglycosylated polypeptide containing 77 amino acids with a molecular mass of 8,759 daltons.Many of the biological functions of C4a are similar to those of C3a, but the specific activities are far below those of C3a.C4a activity is so low, in fact, that it was initially thought to be inactive.These measured activities include inducing muscle contraction in the guinea pig ileum test (spasmogenic activity), desensitization of muscle to C3a stimulation suggesting that the same receptor for both C3a and C4a is involved (tachyphylactic activity) and inducing vascular permeability in human skin (Gorski J.P. et al. (1979)).C4a does not show tachyphylactic activity against C5a or chemotactic activity.Removal of the C-terminal arginine by serum carboxypeptidase N destroys all these activities (Meuller-Ortiz, S.L., et al. (2009)).C4a appears to act through the C3a receptor (C3aR) which is a G-protein coupled receptor found widely distributed on peripheral tissues, lymphoid cells (neutrohphils, monocyes, and eosinophils) and in the central nervous system (astrocytes, neurons and glial cells) (Law, S.K.A. and Reid, K.B.M. (1995)).

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Complement Technology的GVB o是一种基本缓冲液，可用于制备用于补体测定的其他传统缓冲液。可以将Ca ++和Mg ++添加到GVB o中，以制成用于经典途径和凝集素途径测定的GVB ++。可以将MgEGTA添加到GVB o中以进行替代途径测定。EDTA可被添加到GVB Ò准备GVBE抑制补体活化。GVB ø也用于血清和其它测定组分的稀释在许多补体测定中特别是在旁路途径测定（摩根，BP（2000;多兹，AW和Sim，RB（1997））。