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The β-site APP Cleaving enzyme 1 (BACE1) is a membrane-associated aspartyl protease which mediates the production of amyloid-β (Aβ), a major component of amyloid plaques in the Alzheimer's disease brain. We have synthesised and characterised a series of peptidomimetic analogues of BACE substrates that incorporate two distinct stabilising structures. To demonstrate the potential activity of these compounds, a variety of assaying strategies were used to investigate cleavage susceptibility and inhibition potency under competitive and non-competitive conditions. β-Amino acids and scissile site N-methylation were incorporated into peptide substrate templates as transition state isostere (TSI) substitutes by positional scanning to generate series of non-TSI β-peptidomimetics. The amino acid sequences flanking the β-cleavage site within APP carrying the Swedish double mutation (APP_SW), Neuregulin, the synthetic hydroxyethylene-based TSI peptide inhibitor OM99-2, and the high affinity peptide sequence SEISYEVEFR, served as the four substrate templates from which over 60 peptides were designed and synthesised by solid phase peptide synthesis. A quenched fluorescent substrate BACE1 assay in conjunction with liquid chromatography-mass spectrometry (LC-MS) analysis was established to investigate cleavage susceptibility and inhibition potency under competitive and non-competitive conditions. It was determined that β-amino acids substituted at the P¹ scissile site position within known peptide substrates were resistant to proteolysis, and particular substitutions induced a concentration-dependent stimulation of BACE1, indicating a possible modulatory role of native BACE1 substrates.

Item Type:	Refereed Article
Research Division:	Biomedical and Clinical Sciences
Research Group:	Medical biochemistry and metabolomics
Research Field:	Medical biochemistry - proteins and peptides (incl. medical proteomics)
Objective Division:	Health
Objective Group:	Clinical health
Objective Field:	Clinical health not elsewhere classified
UTAS Author:	Small, DH (Professor David Small)
ID Code:	139757
Year Published:	2020
Web of Science® Times Cited:	1
Deposited By:	Menzies Institute for Medical Research
Deposited On:	2020-07-02
Last Modified:	2022-08-26
Downloads:	10 View Download Statistics