Amino acids labeled with [99mTc(CO)3]+ and recognized by the L-type amino acid transporter LAT1.

We have synthesized amino acids conjugated at the alpha-carbon through an alkyl spacer to a small tripod ligand. The tripod coordinates to the fac-[M(CO)3]+ moiety (M = Re, 99mTc). Depending on the lengths of the spacers, these metal complexes with pendent alpha-amino acids are recognized and transported by the l-type amino acid transporter LAT1.