1-Methylpyridinium-4-(4-phenylmethanethiosulfonate) iodide, MTS-MPP+, a novel scanning cysteine accessibility method (SCAM) reagent for monoamine transporter studies.

A novel substituted cysteine accessibility method (SCAM) reagent was developed for monoamine uptake transporters. The new reagent, MTS-MPP(+), was a derivative of the neurotoxin and transporter substrate MPP(+). MTS-MPP(+) labeled cysteine residues introduced into the serotonin transporter protein. Although it did not prove to be a substrate, as is MPP(+), it appears to label cysteine residues lining the permeation pore of the transporter more readily than currently available nonspecific SCAM reagents.