Expression of recombinant pro-neuropeptide Y, proopiomelanocortin, and proenkephalin: relative processing by \u27prohormone thiol protease\u27 (PTP).

The preference of the \u27prohormone thiol protease\u27 (PTP), a candidate prohormone processing enzyme, for different peptide precursors was assessed in vitro with recombinant prohormones near estimated in vivo levels. Pro-neuropeptide Y (pro-NPY), proopiomelanocortin (POMC), and proenkephalin (PE) were expressed at high levels in E. coli. Purification of prohormones utilized a combination of DEAE-Sepharose, Mono Q, and preparative electrophoresis. PTP cleaved PE most readily, and also cleaved pro-NPY. The processing of POMC by PTP was minimal. These results demonstrate PTP\u27s preference for certain prohormone substrates