Pozzi Oscar R, Sajaroff Elisa O, Edreira Martín M
National Atomic Energy Commission, Ezeiza Atomic Centre, Buenos Aires, Argentina.
Appl Radiat Isot. 2006 Jun;64(6):668-76. doi: 10.1016/j.apradiso.2006.01.001. Epub 2006 Feb 17.
The influence of radioiodination made through prosthetic group N-succinimidyl-3-[131I]iodo-benzoate ([131I]SIB) on the behavior of small peptides was investigated using as model the chemotactic hexapeptide Nalpha-for-Nle-Leu-Phe-Nle-Tyr-Lys. No carrier added labeled peptide was isolated by reverse-phase HPLC (RP-HPLC) with coupling efficiencies up to 59-75%. Biodistribution in normal and infected C57 mice showed mainly a hepatobiliary clearance, a very low thyroid uptake and the highest uptake at the infection site was within 1h of injection. Superoxide production and competitive binding assays studies in human polymorphonuclear leukocytes showed a preserved biological activity and high-affinity specific binding. However, the results indicated that the changes observed in the receptor-binding properties with an IC50 almost twice than the unlabeled peptide and the increasing in the hepatobiliary excretion could be the consequence of the increased lipophicity observed due to the presence of the prosthetic group together with a strong influence of the radioisotope per se.
以趋化六肽Nα-对-正亮氨酸-亮氨酸-苯丙氨酸-正亮氨酸-酪氨酸-赖氨酸为模型，研究了通过N-琥珀酰亚胺基-3-[¹³¹I]碘苯甲酸酯（[¹³¹I]SIB）进行放射性碘化对小肽行为的影响。通过反相高效液相色谱（RP-HPLC）分离出无载体添加的标记肽，偶联效率高达59%-75%。在正常和感染的C57小鼠中的生物分布显示，主要通过肝胆清除，甲状腺摄取非常低，感染部位的最高摄取发生在注射后1小时内。在人多形核白细胞中进行的超氧化物产生和竞争性结合试验研究表明，其具有保留的生物活性和高亲和力特异性结合。然而，结果表明，观察到的受体结合特性的变化（IC50几乎是未标记肽的两倍）以及肝胆排泄的增加，可能是由于辅基的存在导致亲脂性增加以及放射性同位素本身的强烈影响所致。
