Inhibition of aminopeptidases by amastatin and bestatin derivatives. Effect of inhibitor structure on slow-binding processes

Abstract

Amastatin [(2S,3R)-3-amino-2-hydroxy-5-methylhexanoyl-L-valyl-L-valyl-L- aspartic acid] and bestatin [(2S,3R)-3-amino-2-hydroxy-4-phenylbutanoyl-L-leucine] are slow-binding, competitive inhibitors of aminopeptidase M (AP-M) with net inhibition constants (Ki) of 1.9 X 10(-8) and 4.1 X 10(-6) M, respectively. The effect of inhibitor structure on net Ki and on slow-binding inhibition was evaluated for analogues of both inhibitors on AP-M and leucine aminopeptidase (LAP). The (2S)-hydroxyl group contributes to the stabilization of a collision complex [EI], which is formed rapidly. In contrast, increasing the peptide chain length of the inhibitor produces more potent inhibitors as a consequence of a slower binding process. A statine analogue of amastatin [(3S,4S)-Sta-Val-Val-Asp] stimulated rather than inhibited LAP. AP-M binds tri- and tetrapeptide inhibitors more strongly than dipeptide inhibitors, whereas LAP binds dipeptide inhibitors more strongly. The difference in binding can be used to distinguish cytosolic from membrane-bound aminopeptidases.

Tachykinin‐induced contraction of the guinea‐pig isolated oesophageal mucosa is mediated by NK2 receptors

“…When tension had returned to baseline, they were added in the same manner until no response resulted (usually after three additions). After washout, captopril, thiorphan and amastatin (20 mM) were then added together, 30 min prior to each concentration-response curve, since the maximum inhibition of aminopeptidases by amastatin has been reported to require a 30 min equilibration period (Rich et al, 1984).…”

Angiotensin-III is Increased in Alzheimer’s Disease in Association with Amyloid-β and Tau Pathology

“…Angiotensin-III (Ang-III) is a heptapeptide produced following aminopeptidase-A (AP-A) (EC 3.4.11.7) mediated cleavage of the Asp residue at the N-terminal of Ang-II [12][13][14][15]. Ang-III is a potent activator of AT1R and AT2R [16,17].…”

Design, synthesis and preliminary activity evaluation of novel 3-amino-2-hydroxyl-3-phenylpropanoic acid derivatives as aminopeptidase N/CD13 inhibitors

“…Since then, many APN inhibitors such as probestin 12 , prebestin 12 , AHPA-Val 13 and amatatin 14 have been developed. Judging from the structure of these compounds, we can see that they all contain the key unit 3-amino-2-hydroxy acyl scaffold, which is important for their biological activity for that it can chelate the Zn 2+ in the active site of metal-dependent enzymes 15 .…”