Gianazza E, Righetti P G
Biochim Biophys Acta. 1978 May 3;540(2):357-64. doi: 10.1016/0304-4165(78)90149-6.
The binding of carrier ampholytes to polyanions is markedly pH-dependent: it is very strong at pH 3, rather weak at pH 5 and abolished at pH 7. Binding is affected by the type of negative charge, its density and spatial orientation on the polyanion. On the basis of the type of negative charge, the binding strength decreases in the following order: polyphosphate greater than polysulphate greater than polycarboxylate. Given the same type of negative charge, the binding is dependent on charge density and its space orientation: thus polyglutamic acid forms stronger complexes than polygalacturonic acid. The minimum length of the polyanion eliciting a measurable binding appears to be of the order of about six negative charges, as demonstrated with hexametaphosphate.
载体两性电解质与聚阴离子的结合明显依赖于pH值：在pH 3时结合非常强，在pH 5时相当弱，在pH 7时则消失。结合受到聚阴离子上负电荷的类型、密度和空间取向的影响。基于负电荷的类型，结合强度按以下顺序降低：聚磷酸盐大于聚硫酸盐大于聚羧酸盐。在负电荷类型相同的情况下，结合取决于电荷密度及其空间取向：因此聚谷氨酸形成的复合物比聚半乳糖醛酸更强。如用六偏磷酸钠所证明的，引发可测量结合的聚阴离子的最小长度似乎约为六个负电荷的量级。
