title: Highly efficient method for125I-radiolabeling of biomolecules using inverse-electron-demand Diels-Alder reaction.
abstract: In this report, we present a rapid and highly efficient method for radioactive iodine labeling of trans-cyclooctene group conjugated biomolecules using inverse-electron-demand Diels-Alder reaction. Radioiodination reaction of the tetrazine structure was carried out using the stannylated precursor 2 to give125I-labeled product ([125I]1) with high radiochemical yield (65±8%) and radiochemical purity (>99%). For radiolabeling application of [125I]1, trans-cyclooctene derived cRGD peptide and human serum albumin were prepared. These substrates were reacted with [125I]1 under mild condition to provide the radiolabeled products [125I]6 and [125I]8, respectively, with excellent radiochemical yields. The biodistribution study of [125I]8 in normal ICR mice showed significantly lower thyroid uptake values than that of125I-labeled human serum albumin prepared by a traditional radiolabeling method. Therefore [125I]8 will be a useful radiolabeled tracer in various molecular imaging and biological studies. Those results clearly demonstrate that [125I]1 will be used as a valuable prosthetic group for radiolabeling of biomolecules.
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea.
authors.forename: Mi Hee
authors.initials: MH
authors.lastname: Choi
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea.
authors.forename: Ha Eun
authors.initials: HE
authors.lastname: Shim
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea.
authors.forename: Seong-Jae
authors.initials: SJ
authors.lastname: Yun
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea.
authors.forename: Hye Rim
authors.initials: HR
authors.lastname: Kim
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea; Department of Radiation Biotechnology and Applied Radioisotope Science, Korea University of Science and Technology, Deajeon 34113, Republic of Korea.
authors.forename: Sajid
authors.initials: S
authors.lastname: Mushtaq
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea.
authors.forename: Chang Heon
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea; Department of Radiation Biotechnology and Applied Radioisotope Science, Korea University of Science and Technology, Deajeon 34113, Republic of Korea.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Park
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea.
authors.forename: Dae Seong
authors.initials: DS
authors.lastname: Choi
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea.
authors.forename: Dong-Eun
authors.initials: DE
authors.lastname: Lee
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea; Department of Radiation Biotechnology and Applied Radioisotope Science, Korea University of Science and Technology, Deajeon 34113, Republic of Korea.
authors.forename: Eui-Baek
authors.initials: EB
authors.lastname: Byun
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea; Department of Radiation Biotechnology and Applied Radioisotope Science, Korea University of Science and Technology, Deajeon 34113, Republic of Korea. Electronic address: jangbs@kaeri.re.kr.
authors.forename: Beom-Su
authors.initials: BS
authors.lastname: Jang
authors.affiliation: Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk 56212, Republic of Korea; Department of Radiation Biotechnology and Applied Radioisotope Science, Korea University of Science and Technology, Deajeon 34113, Republic of Korea. Electronic address: jeonj@kaeri.re.kr.
authors.forename: Jongho
authors.initials: J
authors.lastname: Jeon
keywords: Bioorthogonal reaction; Inverse-electron-demand Diels–Alder reaction; Radioactive iodine; Radiolabeling; Radiotracer