ABSTRACT
This chapter reviews the identification and purification of EC-proteins and peptides, structure analysis, and their enzymatic processing by using high-performance liquid chromatography (HPLC). However, the method of combination of radioimmunoassay and HPLC has made it possible to determine the exact amount of EC-peptides after they are separated using a calibrated HPLC column. The specificity of this HPLC-immunochemical detection is like a two dimensional electrophoresis or TLC. Since the discovery of Met-enkephalin and Leu-enkephalin in 1975, opioid peptides and its precursors have been effectively studied using HPLC. The data on the primary structures of EC-peptides shows great similarities between human and bovine proenkephalin. Though structures of the three precursors of enkephalins have been revealed, many questions are especially for the processing, and physiological and pharmacological roles. R. Possenti et al. examined enkephalin-binding systems in human plasma by HPLC with the combination of reverse-phase and gel-filtration columns.
