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Updated: Aug 8, 2025
Identifying Protein-protein Interaction Sites Using Peptide Arrays
Published on: November 18, 2014
An Efficient Peptidomics Screening for Exogenous Substrates and Inhibitory Peptides of the Dipeptidase ACE from Milk
Ju-Hsuan Huang1, Nhung Thi Phuong Nong2,3, Jue-Liang Hsu1,4,5
1Department of Biological Science and Technology, National Pingtung University of Science and Technology, 1 Shuefu Road, Neipu, Pingtung 91201, Taiwan.
Abstract:
The dipeptidase angiotensin-I-converting enzyme (ACE) pre-incubation, liquid chromatography- mass spectrometry (LC-MS), and stable-isotope labeling were integrated for an efficient screening of ACE's exogenous substrates from milk hydrolysate. Using this approach, 31 substrates were readily identified from 478 identified peptides and their activities were confirmed using synthetic peptides. Their reactivity is highly correlated with the decreased isotope ratio observed in LC-MS. Among these substrates, the most frequently observed residue at the P1' position was Leu/Ser. It also revealed that ACE would not cleave the peptide when P1' is Pro, P2' is Asp/Glu, or P1 position is Ile. Interestingly, the sequential two-stage hydrolysis was also found. Moreover, their protective effects against ACE-mediated hydrolysis of angiotensin I (Ang-I) were also examined. The result indicated that AYFYPELFR and HLPLPLLQSW can significantly retard the hydrolysis of Ang-I and act as substrate-type inhibitors.
