Analysis of the binding sites with NL-101 to amino acids and peptides by HPLC/MS/MS

The binding between NL-101, a novel nitrogen mustard anti-cancer drug, with amino acids and peptides has been investigated by high performance liquid chromatography electrospray tandem mass spectrometry (HPLC/ESI-MS/MS). This study offers supporting data of the interaction among drug and amino acids and peptides, which could potentially explain the cytotoxic and mutagenic effects of the drug. Collision-induced dissociation (CID) experiment demonstrated that under the same collision energy, the amino group combined with NL-101 adducts are sensitive and often produce more fragment ions; the carboxyl group combined with NL-101 adducts are hard to break and display fewer fragment ions. In addition, when other group (like sulfhydryl group) of amino acids binds to NL-101, CID spectra show different fragmentation pattern. These differences could display structural information about the drug adducts and be utilized as location of the authentic binding sites.