title: Solid-phase synthesis of a peptide derivative of thymosin alpha1 and initial studies on its (99m)Tc-radiolabelling.
abstract: A derivative (1) of the immunopotentiating 28-peptide thymosin alpha1 has been especially designed, so that it can be (99m)Tc-radiolabelled, and synthesized following the Fmoc solid-phase peptide synthesis approach. Derivative 1 contains the N-terminal fragment Talpha1[1-14] as a bioactive segment, at the C-terminus of which a (99m)Tc-chelating moiety consisting of N(alpha),N(alpha)-dimethylglycine, serine and cysteine is linked through the N(epsilon)-amino group of a 'bifunctional' lysine residue; the latter is indirectly anchored on the solid-phase peptide synthesis resin through 6-aminocaproic acid (dmGSCK{N(epsilon)-Talpha1[1-14]}Aca). Synthetic derivative 1 was obtained at high overall yield (approximately 35%) and purity (>95%) and shown to be efficiently radiolabelled with (99m)Tc, thus resulting in the first, to our knowledge, so far reported (99m)Tc-radiolabelled derivative of thymosin alpha1, which may be eventually used as a specific molecular tool for the in vitro/in vivo study of the mode of action of the parent bioactive peptide.
authors.affiliation: National Centre for Scientific Research 'Demokritos', Aghia Paraskevi Attikis, Athens 15310, Greece.
authors.forename: Persefoni
authors.initials: P
authors.lastname: Klimentzou
authors.forename: Alexander
authors.initials: A
authors.lastname: Beck
authors.forename: Alexandra
authors.initials: A
authors.lastname: Varvarigou
authors.forename: Ourania
authors.initials: O
authors.lastname: Tsitsilonis
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Voelter
authors.forename: Ioannis
authors.initials: I
authors.lastname: Pirmettis
authors.forename: Minas
authors.initials: M
authors.lastname: Papadopoulos
authors.forename: Evangelia
authors.initials: E
authors.lastname: Livaniou
authors.forename: Christos
authors.initials: C
authors.lastname: Zikos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D008969:Molecular Sequence Data; D015394:Molecular Structure; D015609:Organotechnetium Compounds / Q000737:chemistry*; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000235:genetics; D019275:Radiopharmaceuticals / Q000737:chemistry*; D000077596:Thymalfasin; D013947:Thymosin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D015609:Organotechnetium Compounds; D010455:Peptides; D019275:Radiopharmaceuticals; D013947:Thymosin; D000077596:Thymalfasin