Product Description

SGVB⁺⁺ is a specialized buffer which is low in ionic strength (due to the low NaCl concentration), but isotonic (due to the sucrose).This combination of properties allows complement assays or binding assays to be performed with cells at low ionic strength, which improves binding, while the sucrose keeps the cells from lysing due to the high concentration of sucrose.This buffer is practically identical to DGVB buffer except that they use D-glucose instead of sucrose to maintain their isotonic characteristic.These buffers are isotonic with VBS, GVB, PBS, etc. meaning that the osmotic pressure on cell membranes will be the same even though the salt concentration is low.SGVB⁺⁺ buffer is especially useful in C1 assays (Dodds, A.W. and Sim, R.B. (1997)) and in binding assays such as those measuring the binding of factor B or factor H to EsC3b cells (sheep erythrocytes bearing surface-bound C3b) (Pangburn, M.K. and Muller-Eberhard, H.J. (1978); Pangburn, M.K., et al. (1980)).These interactions are sensitive to the salt concentration and lowering the ionic strength can enhance binding 5- to 10-fold.

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Complement Technology的C1是级联反应中的第一个补体成分，称为补体经典途径。C1与抗原结合的抗体（免疫复合物）结合并被其激活，从而产生引发级联反应的蛋白酶。C1实际上是钙依赖性复合物中结合在一起的三种不同蛋白质（C1q，C1r和C1s）的非共价复合物。C1q通过其六个臂中的两个或多个与IgG或IgM的Fc结构域结合。多臂与免疫复合物的结合被认为会引入压力，从而导致复合物中的两个C1r蛋白（蛋白酶酶原）自身激活，从而产生两种活性的C1r丝氨酸蛋白酶（Morikis，D.和Lambris，JD（2005））。 。这些激活的C1r亚基裂解并激活复合物中的两个C1s蛋白酶酶原。活化的C1裂解补体成分C4，释放出C4a，并启动C4b与活化表面的共价连接。活化的C1也切割C2，并且C2的较大片段结合至表面附着的C4b，形成C4b，C2a，其为经典途径的C3 / C5转化酶。