N-(m-[125I]iodophenyl)maleimide: an agent for high yield radiolabeling of antibodies.
In an effort to radiolabel antibodies, N-(m-[125I]iodophenyl)maleimide (m-[125I]IPM) was prepared by the demetallation of an N-[m-tri-(n-butyl)stannylphenyl]maleimide intermediate. The unlabeled intermediate was synthesized in greater than or equal to 75% yield using a palladium catalyzed reaction of hexabutylditin with m-bromoaniline, followed by reaction with maleic anhydride and ring annulation. All products were confirmed by NMR and elemental analysis. Labeling with 125I was carried out in a biphasic mixture containing chloramine-T (radiochemical yield greater than or equal to 70%). Rabbit IgG modified with the heterobifunctional crosslinking agent N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP) and bovine serum albumin were conjugated with m-[125I]IPM (yield: 40 and 80%, respectively). In addition, m-[125I]IPM was conjugated to rabbit IgG subunits (HL) in 70% yield. The in vitro stability of the radiolabeled proteins in serum showed less than 1% deiodination over 24 h.
Khawli
L A
LA
Department of Radiology (Nuclear Medicine), Harvard Medical School, Shields Warren Radiation Laboratory, Boston, MA 02115.
van den Abbeele
A D
AD
Kassis
A I
AI
D000818:Animals; D000906:Antibodies / Q000737:chemistry*; D004355:Drug Stability; D007074:Immunoglobulin G / Q000737:chemistry; D007457:Iodine Radioisotopes; D007462:Iodobenzenes / Q000138:chemical synthesis* / Q000737:chemistry; D007553:Isotope Labeling / Q000379:methods*; D008301:Maleimides / Q000138:chemical synthesis* / Q000737:chemistry; D051379:Mice; D011817:Rabbits; D012710:Serum Albumin, Bovine / Q000737:chemistry
D000906:Antibodies; D007074:Immunoglobulin G; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D008301:Maleimides; C075714:N-(3-iodophenyl)maleimide; D012710:Serum Albumin, Bovine