Interaction of peptide YY with rat intestinal epithelial plasma membranes: binding of the radioiodinated peptide.
Interaction of peptide YY with rat intestinal epithelial plasma membranes: binding of the radioiodinated peptide.
复制标题
肽 YY 与大鼠肠上皮质膜的相互作用：放射性碘标记肽的结合。
作者：
M. Laburthe;B. Chenut;C. Rouyer‐Fessard;K. Tatemoto;A. Couvineau;A. Servin;B. Amiranoff
通过研究125 I标记的肽YY与膜的相互作用的动力学、化学计量学和化学特异性，在大鼠空肠上皮细胞制备的质膜中鉴定并表征了肽YY（PYY）的高亲和力结合位点。[125 I]PYY的结合是快速的、可饱和的、可逆的、特异性的，并且依赖于温度、pH和离子强度。在优化的结合稳态条件下（15 ℃下孵育2小时），[125 I] PYY和结合位点的降解均不超过20%。PYY结合的浓度依赖性，通过加入增加浓度的[125 I]PYY测定，表明特异性结合在2-3 nM肽饱和。Scatchard分析揭示了一类结合位点，解离常数（Kd）为434 +/-（SE）56 pM，结合容量为336 +/- 41 fmol/mg蛋白（n = 11）。当将增加浓度的未标记PYY加入固定浓度的[125 I]PYY中时，获得相同的结果，表明放射性碘标记肽与天然PYY具有相同的表观亲和力。结构上与PYY无关的肽，例如血管活性肠肽家族的成员、胰岛素或胆囊收缩素八肽，无法与[125 I]PYY竞争与膜的结合。大鼠、人和禽类胰腺多肽分别与PYY具有42%、47%和53%的同源性，它们确实抑制[125 I]PYY结合，但效力比PYY低约100，000倍，表明PYY结合位点识别的严格结构要求。相比之下，天然或合成的神经肽Y，其36个氨基酸中有25个与PYY相同，保留了对PYY结合位点的高亲和力[仅比PYY低4.7 +/-1.2（n = 5）倍]。特异性[125 I]PYY结合在小肠上部特别高，在胃、大肠或肝脏中无法检测到。这些发现表明，大鼠小肠上皮细胞表达候选肠道激素PYY的特异性结合位点，该位点也以高亲和力结合神经肽Y，这表明这两种肽可以通过与共同受体位点的相互作用来调节小肠上皮细胞的功能。
High affinity binding sites for peptide YY (PYY) have been identified and characterized in plasma membranes prepared from rat jejunal epithelium by studying the kinetics, stoichiometry, and chemical specificity of the interaction of 125I-labeled PYY with membranes. Binding of [125I]PYY was rapid, saturable, reversible, specific, and depended on temperature, pH, and ionic strength. In optimized steady state conditions of binding (2 h of incubation at 15 C), the degradation of both [125I] PYY and binding sites did not exceed 20%. The concentration dependence of PYY binding, determined by adding increasing concentrations of [125I]PYY, indicated that specific binding saturated at 2-3 nM peptide. Scatchard analysis revealed a single class of binding sites with a dissociation constant (Kd) of 434 +/- (SE) 56 pM and a binding capacity of 336 +/- 41 fmol/mg protein (n = 11). Identical results were obtained when increasing concentrations of unlabeled PYY were added to a fixed concentration of [125I]PYY, indicating that the radioiodinated peptide has the same apparent affinity as native PYY. Peptides structurally unrelated to PYY, such as members of the vasoactive intestinal peptide family, insulin, or cholecystokinin octapeptide, were unable to compete with [125I]PYY for binding to membranes. Rat, human, and avian pancreatic polypeptides, which display, respectively, 42%, 47%, and 53% homology with PYY, did inhibit [125I]PYY binding but with an approximate or equal to 100,000-fold lower potency than PYY, indicating the strict structural requirement for recognition by PYY binding sites. In contrast, natural or synthetic neuropeptide Y, which has 25 out of 36 amino acids in common with PYY, retained a high affinity for PYY binding sites [only 4.7 +/- 1.2 (n = 5) times lower than that of PYY]. Specific [125I]PYY binding was particularly high in the upper small intestine and could not be detected in stomach, large intestine, or liver. These findings indicate that rat small intestinal epithelium expresses specific binding sites for the candidate gut hormone PYY that also binds the neuropeptide Y with high affinity, suggesting that the two peptides may regulate the function of small intestinal epithelium, through interaction with a common receptor site.
来自大鼠胰腺的胰多肽。
影响因子：
4.8
作者：
Kimmel,JR;Pollock,HG;Chance,RE;Johnson,MG;ReeveJr,JR;Taylor,IL;Miller,C;Shively,JE
通讯作者：
Shively,JE
影响因子：
29.4
作者：
I. Taylor
通讯作者：
I. Taylor