Vera D R, Krohn K A, Stadalnik R C, Scheibe P O
J Nucl Med. 1984 Jul;25(7):779-87.
Hepatic binding protein (HBP) is a membrane receptor that binds and transports plasma glycoproteins from hepatic blood to hepatocellular lysosomes. We have characterized the in vitro binding of Tc-99m galactosyl-neoglycoalbumin (Tc-NGA), a synthetic HBP ligand, to liver membrane. Structural modifications of NGA resulted in the alteration of the equilibrium constant, KA, and the forward-binding rate constant, kb. Binding was second-order; the relative amount of membrane-bound NGA depended on the initial concentrations of ligand and membrane. Membrane displacement studies, using carrier ligands in contrast to previously bound Tc-NGA or I-NGA, correlated with the binding characteristics of a native HBP ligand, asialo-orosomucoid. We used computer simulation to study the detectability of the changes in HBP concentration at different values of kb. The simulations indicated that radiopharmacokinetic sensitivity to alterations in [HBP] should be possible using a neoglycoalbumin preparation with a carbohydrate density within the range of 15 to 25 galactose units per albumin molecule.
肝结合蛋白（HBP）是一种膜受体，它能结合血浆糖蛋白并将其从肝血转运至肝细胞溶酶体。我们已对合成的HBP配体锝-99m半乳糖基新糖白蛋白（Tc-NGA）与肝细胞膜的体外结合进行了表征。NGA的结构修饰导致平衡常数KA和正向结合速率常数kb发生改变。结合是二级反应；膜结合NGA的相对量取决于配体和膜的初始浓度。与先前结合的Tc-NGA或I-NGA相比，使用载体配体进行的膜置换研究与天然HBP配体去唾液酸血清类黏蛋白的结合特性相关。我们使用计算机模拟来研究在不同kb值下HBP浓度变化的可检测性。模拟结果表明，使用每分子白蛋白中碳水化合物密度在15至25个半乳糖单位范围内的新糖白蛋白制剂，对[HBP]变化的放射性药代动力学敏感性应该是可行的。
