Production of functional peptides with inhibition ability against angiotensin I-Converting enzyme using P. pastoris expression system

To obtain the angiotension-I converting enzyme inhibitor (ACEI), a fusion ACEI polypeptideencoded with 8 DNA sequences of GPL, GPM, IKW, IVY, IRPVQ, IWHHT, IYPRY and IAPG,which were selected and designed and cloned into pGAPZaC and then transformed intoPichia pastoris SMD1168H. After 3 days induction, the fraction with highest ACEI activity wasexpressed and purified using a Ni Sepharose™ 6 Fast Flow. The IC50 of recombinant ACEIpolypeptide was 88.2 mM. A 128-fold increase of ACEI activity (0.69 mM) was obtained afterpepsin digestion, which was equivalent to 0.022 mM of captopril. Reverse phase HPLCindicated all the 8 peptides contained in ACEI-hydrolysate after pepsin digestion.