Trifluoroacetyl-HYNIC Peptides: Synthesis and 99mTc Radiolabeling
journal contributionposted on 22.03.2007, 00:00 by M. Bashir-Uddin Surfraz, Robert King, Stephen J. Mather, Stefano C. G. Biagini, Philip J. Blower
Fmoc-lys(HYNIC-Boc)-OH, a precursor for solid-phase synthesis of 99mTc-labeled peptides, was synthesized efficiently without HPLC purification. HPLC-ESMS showed that deprotection and decoupling of peptide from the resin with trifluoroacetic acid gave initially HYNIC-peptide, which was trifluoroacetylated upon prolonged incubation. The trifluoroacetyl-HYNIC group was hydrolyzed during 99mTc labeling, rendering deprotection unnecessary. Trifluoroacetyl-HYNIC peptide was 99mTc-labeled as efficiently, producing the same product, as HYNIC-peptide. These modifications enhance the versatility of HYNIC for 99mTc peptide labeling.