Livaniou E, Evangelatos G P, Ithakissios D S
J Nucl Med. 1987 Sep;28(9):1430-4.
The synthesis of two radioiodinated biotin derivatives with the biotin-ureido group intact is described. This synthesis was performed by coupling (pH 8.5, 20-22 degrees C, 90 min) N-hydroxysuccinimidobiotin to tyramine, which was radioiodinated prior to this using a modified chloramine-T method. Two derivatives were produced, the N-[beta-(4-OH-3-125I-phenyl)ethyl] and the N-[beta-(4-OH-3,5-di 125I-phenyl)ethyl] biotin amides, depending on the amount of tyramine used in the radioiodination reaction. The final products were separated by thin layer chromatography (n-butanol: 2N NH4OH: ethanol, 3:1:1, v/v/v). The radioiodinated derivatives that were synthesized or their resulting mixture were found to complete with biotin for the avidin-binding sites; thus, they were capable of being used as tracers in biotin radioassays. The specific activity of their mixture was high-greater than 350 Ci/mmol-and they were stable for 2 mo at 4 degrees C.
描述了两种生物素-脲基完整的放射性碘化生物素衍生物的合成。该合成是通过将N-羟基琥珀酰亚胺生物素与酪胺偶联（pH 8.5，20-22℃，90分钟）进行的，酪胺在此之前使用改良的氯胺-T法进行放射性碘化。根据放射性碘化反应中使用的酪胺量，产生了两种衍生物，即N-[β-(4-OH-3-¹²⁵I-苯基)乙基]和N-[β-(4-OH-3,5-二¹²⁵I-苯基)乙基]生物素酰胺。最终产物通过薄层色谱法（正丁醇：2N NH₄OH：乙醇，3:1:1，v/v/v）分离。发现合成的放射性碘化衍生物或其所得混合物与生物素竞争抗生物素蛋白结合位点；因此，它们能够用作生物素放射测定中的示踪剂。它们混合物的比活度很高——大于350 Ci/mmol——并且在4℃下稳定2个月。
