^（99m）Tc－新半乳糖白蛋白体外受体介导结合特性的研究

Characterization of Receptor-Mediated Binding of99mTc-NGA in vitro

本文报道￣９９ｍＴｃ－新半乳糖白蛋白（￣９９ｍＴｃ－ＮＧＡ）与大鼠肝细胞膜进行体外结合试验。结果表明：￣９９ｍＴｃ－ＮＧＡ系与肝细胞膜上的高亲和力低容量（Ｋ＿１：８．４０８９×１０￣９Ｌ／ｍｏｌ；Ｒ＿１：１．７３５０×１０￣（－１２）ｍｏｌ／ｍｇ）和低亲和力高容量（Ｋ＿２：２．０８２７×１０￣８Ｌ／ｍｏｌ；Ｒ＿２：６．９５３０×１０￣（－１２）ｍｏｌ／ｍｇ）２个结合位点相结合，其结合表现出高特异性、可饱和性及对细胞膜蛋白浓度的线性依赖性，具备受体介导结合的基本特征。￣（９９ｍ）Ｔｃ－ＮＧＡ是一个很有希望的肝受体显像剂。

This paper reports results of an assayof the binding of￣99mTc-galactosylneoglycoalbumin(NGA)and plasma membranes of the rat liver invitro. The data showed that ￣99mTc-NGA could bebund to the membrane receptor with high affinity.Specificity and saturability,and that the amount ofmembrane-bound ￣99mTc-NGA varied linearly with theamount of membrane within each reaction tube. Thebiphasic curve of scatchard plot revealed that ￣99mTc-NGA was bound to two sites of the receptor with dif-ferent affinity and concentration( K_1 8. 4089×10￣9L/mol,R_1. 7350×10￣(-12)mol/mg);K_2 2.0827×10￣8L/mol,R_2 6. 9530×10￣(-12) mol/mg ). Therefore, the au-thors consider that ￣99mTc-NGA is a promising hepaticreceptor agent for imaging。