Dickinson K E, Schachter M, Miles C M, Coy D H, Sever P S
Peptides. 1986 Sep-Oct;7(5):791-800. doi: 10.1016/0196-9781(86)90097-5.
125I-VIP bound specifically to sites on human, rat, guinea pig, and rabbit lung membranes with a dissociation constant (KD) of 60-200 pM and binding site maxima of 200-800 fmol/mg of protein. The presence of a second lower affinity site was detected but not investigated further. High affinity 125I-VIP binding was reversible and displaced by structurally related peptides with an order of potency: VIP greater than rGRF greater than PHI greater than hGRF greater than secretin = Ac Tyr1 D Phe2 GRF. 125I-VIP has been covalently incorporated into lung membranes using disuccinimidyl suberate. Sodium dodecyl sulfate-polyacrilamide gel electrophoresis of labeled human, rat, and rabbit lung membranes revealed major 125I-VIP-receptor complexes of: Mr = 65,000, 56,000, and 64,000 daltons, respectively. Guinea pig lung membranes exhibited two 125I-VIP-receptor complexes of Mr = 66,000 and 60,000 daltons. This labeling pattern probably reflects the presence of differentially glycosylated forms of the same receptor since treatment with neuroaminidase resulted in a single homogeneous band (Mr = 57,000 daltons). Soluble covalently labeled VIP receptors from guinea pig and human lung bound to and were specifically eluted from agarose-linked wheat germ agglutinin columns. Our studies indicate that mammalian lung VIP receptors are glycoproteins containing terminal sialic acid residues.
125I-血管活性肠肽（VIP）特异性结合于人、大鼠、豚鼠和兔肺膜上的位点，解离常数（KD）为60 - 200皮摩尔，结合位点最大值为200 - 800飞摩尔/毫克蛋白质。检测到存在第二个低亲和力位点，但未作进一步研究。高亲和力的125I-VIP结合是可逆的，且被结构相关的肽所取代，其效力顺序为：VIP大于大鼠生长激素释放因子（rGRF）大于肽组氨酸异亮氨酸（PHI）大于人生长激素释放因子（hGRF）大于促胰液素 = 乙酰酪氨酰1 - D - 苯丙氨酰2 - 生长激素释放因子（Ac Tyr1 D Phe2 GRF）。125I-VIP已通过辛二酸二琥珀酰亚胺酯共价结合到肺膜中。对标记的人、大鼠和兔肺膜进行十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳显示，主要的125I-VIP受体复合物的分子量分别为：65,000、56,000和64,000道尔顿。豚鼠肺膜表现出两种分子量分别为66,000和60,000道尔顿的125I-VIP受体复合物。这种标记模式可能反映了同一受体不同糖基化形式的存在，因为用神经氨酸酶处理后产生了一条单一的均匀条带（分子量 = 57,000道尔顿）。来自豚鼠和人肺的可溶性共价标记VIP受体与琼脂糖偶联的麦胚凝集素柱结合并被特异性洗脱。我们的研究表明，哺乳动物肺VIP受体是含有末端唾液酸残基的糖蛋白。
