Krilis S, Lewis R A, Corey E J, Austen K F
J Clin Invest. 1983 Oct;72(4):1516-9. doi: 10.1172/JCI111109.
Specific receptors for leukotriene C4 (LTC4) have been identified on an intact smooth muscle cell line, DDT1 MF-2 cells derived from the Syrian hamster vas deferens. Specific [3H]LTC4 binding at a fixed input at 4 degrees C was rapid, reached a plateau at 86% of total binding at 60 min, and was reversible upon addition of excess homoligand. With incremental inputs of radioligand and a constant cell number, specific [3H]LTC4 binding reached a plateau indicative of saturable binding sites. LIGAND analysis of the Scatchard plot demonstrated a single high affinity binding site with a dissociation constant (Kd) of 5 nM. With incremental inputs of unlabeled LTC4, LIGAND analysis of the Scatchard plot demonstrated a single high affinity site with a Kd of 4.4 nM and in some experiments an additional low affinity site with a Kd of 634 nM. The myotonically active structural analogues of LTC4, 5(R),6(S)-LTC4, 11-trans-LTC4, and C1-monoamide-LTC4, competed effectively with radiolabeled LTC4 such that the relative Kd values of these heteroligands were within one log of that of the homoligand. In contrast, the other native sulfidopeptide leukotrienes, leukotriene D4 and leukotriene E4, exhibited relative Kd values that were 2-3 logs less than that of LTC4. Thus, the high affinity receptor on the DDT1 smooth muscle cell line is specific for a single constituent, LTC4, of slow reacting substance of anaphylaxis.
在一种完整的平滑肌细胞系（源自叙利亚仓鼠输精管的DDT1 MF - 2细胞）上已鉴定出白三烯C4（LTC4）的特异性受体。在4℃下，固定输入量的特异性[3H]LTC4结合迅速，在60分钟时达到总结合量的86%并趋于平稳，加入过量同源配体后结合可逆。随着放射性配体输入量增加而细胞数量恒定，特异性[3H]LTC4结合达到平稳，表明存在可饱和的结合位点。Scatchard图的LIGAND分析显示有一个解离常数（Kd）为5 nM的单一高亲和力结合位点。随着未标记LTC4输入量增加，Scatchard图的LIGAND分析显示有一个Kd为4.4 nM的单一高亲和力位点，在一些实验中还有一个Kd为634 nM的低亲和力位点。LTC4的具有肌强直活性的结构类似物5(R),6(S)-LTC4、11-反式-LTC4和C1-单酰胺-LTC4能有效地与放射性标记的LTC4竞争，使得这些异源配体的相对Kd值与同源配体的Kd值相差在一个对数范围内。相比之下，其他天然硫醚肽白三烯，白三烯D4和白三烯E4，其相对Kd值比LTC4小2 - 3个对数。因此，DDT1平滑肌细胞系上的高亲和力受体对过敏反应慢反应物质的单一成分LTC4具有特异性。
