Reversed-phase high-performance liquid chromatography for the determination of haemorphin-like immunoreactivity in human cerebrospinal fluid.

The haemorphins are opioid peptides derived form the blood protein haemoglobin. This study was focused on the detection and determination of haemorphin-like immunoreactivity in human cerebrospinal fluid (CSF) by reversed-phase HPLC. For this purpose a SMART System, optimized for micropurification, was applied. Prior to application to HPLC, the peptide fraction of the CSF sample was extracted using a reversed-phase silica gel cartridge (Sep-Pak C18). In the HPLC separation, the peptide-like material associated with haemorphin-7 immunoreactivity was recovered and determined using a UV detector. The tryptophan residue present in the haemorphin sequence allowed UV detection at wavelengths (e.g., 276 nm) where interference with other co-eluting peptides lacking this residue is minimized. Recorded levels of haemorphin-like immunoreactivity were compared with those detected by radioimmunoassay.