pe
pep-04671 v1 CC-BY-SA-4.0

Bradykinin-potentiating peptide 12c

A small peptide that blocks ACE, the enzyme that raises blood pressure, helping to lower blood pressure; experimental, not yet an approved drug.

statusbioassayed targetACE length9 aa refs1
anti-hypertensive
EARLY ENTRY This candidate is newly indexed — supporting evidence is still being added. Have a paper or data point? Contribute below.
status 2 / 5 · 0 verified on platform
prediction metrics boltz-2 1.0
ipTM0.770
pTM0.638
avg pLDDT88.7
ranking score0.863
STRUCTURE · PEP-04671 × ACE
ranking0.863
target interface 4.5Å peptide drag rotate · ctrl+scroll zoom · right-click pan
boltz-2 1.0 · mmCIF ↓ download
sequence9 aa
159
EWPRPQIPP
Hypotheses4 directions▾ collapse

Research directions for this peptide, selected from the current sources — hypotheses you can explore and model. None of it is proven yet; tap any one to see the full thinking.

openupdated 2026-06-11

Does the extra amino-acid segment at the front of BPP-12c make it grip ACE more tightly than shorter peptides?

If true, it would explain why snake-venom BPPs outperform simple food peptides at lowering blood pressure, and could guide design of tighter ACE inhibitors for hypertension.

The hypothesis
BPP-12c (EWPRPQIPP) binds ACE primarily through its C-terminal IPP tripeptide motif acting as a competitive active-site inhibitor, with the N-terminal EWP segment providing secondary contacts that distinguish its potency from shorter BPPs lacking this N-terminal extension.
Why it’s plausible
The C-terminal IPP sequence is a well-established ACE inhibitor pharmacophore present in food-derived peptides. BPP-12c carries this motif plus an N-terminal EWP extension containing a bulky Trp. The ipTM of 0.77 supports a stable ACE complex. The EWP segment could reach secondary subsites (S2' pocket) that shorter IPP-only peptides miss, explaining the 'potentiating' label.
Why it matters
If the EWP extension contributes independent ACE contacts beyond the IPP anchor, it explains why BPPs are more potent than plain tripeptides and guides truncation/extension engineering to maximize ACE inhibition.
Plausibility.80
Novelty.55
Impact.70
Basis · grounding3 computed/notes
[1]
sequenceC-terminal IPP motif (positions 7-9) is a canonical ACE inhibitor pharmacophore; three prolines in the 9-aa sequence constrain conformation.
[2]
structureBoltz-2 ipTM=0.77 and pLDDT=88.7 indicate a structurally confident ACE-peptide complex model.
[3]
noteAnnotated target is ACE; peptide is tagged anti-hypertensive.
openupdated 2026-06-11

Does the large tryptophan residue in BPP-12c cause it to fit into only one of ACE's two binding pockets?

If BPP-12c targets only the C-domain of ACE, it could lower blood pressure with fewer side effects than broadly acting ACE inhibitor drugs currently in clinical use.

The hypothesis
BPP-12c selectively inhibits the C-domain active site of ACE over the N-domain active site because its Trp2-Pro3 dipeptide creates a steric or electrostatic barrier that is accommodated by the wider C-domain but not the narrower N-domain tunnel.
Why it’s plausible
ACE has two catalytic domains (N and C) with overlapping but distinct substrate preferences; C-domain selective inhibitors show fewer side effects (less interference with N-domain substrates like AcSDKP). The bulky Trp in BPP-12c could sterically favor the more spacious C-domain. If confirmed, this selectivity profile would distinguish BPP-12c from non-selective ACE inhibitors like captopril.
Why it matters
C-domain selectivity is a sought-after property because it could retain antihypertensive efficacy while reducing side effects associated with blocking N-domain-mediated peptide processing.
Plausibility.65
Novelty.60
Impact.75
Basis · grounding2 computed/notes
[1]
sequenceTrp at position 2 is bulky (214 Da side chain) and flanked by Pro on each side, creating a rigid wedge that may be sterically sorted by ACE domain tunnels of different widths.
[2]
structureipTM=0.77 for the complex is consistent with tight, domain-specific docking rather than low-confidence multi-domain binding.
openupdated 2026-06-11

Could a ring-shaped version of BPP-12c survive stomach acids and still block ACE?

If cyclization preserves ACE-blocking activity while resisting digestion, it could convert this venom peptide into a pill-form antihypertensive, making it accessible and practical for daily use.

The hypothesis
Cyclization of BPP-12c by linking its N-terminal Glu to a Lys substituted at the C-terminus would lock the PPII conformation and confer protease resistance while preserving ACE inhibitory activity, yielding an orally bioavailable peptidomimetic.
Why it’s plausible
BPP-12c's proline-rich core already predisposes a PPII conformation. Head-to-tail cyclization via lactam bond (Glu1 side chain carboxyl to Lys9 epsilon amine, substituting the terminal Pro9) would rigidify this conformation permanently, resist N- and C-terminal exopeptidases (the main route of BPP degradation), and potentially allow oral delivery. The Glu at position 1 provides the reactive handle without synthetic modification of the pharmacophoric residues.
Why it matters
Natural BPPs are degraded rapidly in vivo; a cyclic analog with equivalent potency and oral bioavailability would be a realistic antihypertensive drug candidate derived from a venom-validated scaffold.
Plausibility.60
Novelty.60
Impact.65
Basis · grounding1 paper · 1 computed/note
[1]
sequenceGlu1 provides a side-chain carboxylate for lactam cyclization; replacing Pro9 with Lys9 introduces the amine handle without disrupting the IPP pharmacophore at positions 7-8.
[2]
paper
BPP-10c biodistribution studies indicate rapid clearance, motivating stability engineering for this peptide family.
doi: 10.1016/j.toxicon.2008.06.024
openupdated 2026-06-11

Does BPP-12c's stiff structure mean it loses less energy fitting into its target compared to floppy peptides?

If pre-organization drives potency, it would offer a blueprint for designing compact, rigid peptide drugs for hypertension that are harder to digest and easier to dose.

The hypothesis
The high proline content of BPP-12c (33%, positions 3, 5, 8, 9) enforces a polyproline-II-like helical backbone conformation that pre-organizes the peptide for ACE binding, making entropy loss upon binding smaller compared to more flexible peptides of the same length.
Why it’s plausible
Three prolines in nine residues, including a C-terminal PP dipeptide, strongly constrain phi/psi angles into a PPII-like extended structure. Pre-organized ligands incur less conformational entropy loss on binding. If BPP-12c arrives at ACE already in its bound conformation, binding affinity is higher per unit of sequence than for flexible analogs, which has implications for oral stability and potency.
Why it matters
Entropic pre-organization is a leverage point for peptide drug optimization; confirming it here would validate a design principle for engineering shorter, stiffer ACE-inhibitory peptides.
Plausibility.70
Novelty.45
Impact.55
Basis · grounding2 computed/notes
[1]
sequenceEWPRPQIPP: P at positions 3, 5, 8, 9 (numbering from 1). C-terminal PP dipeptide strongly disfavors flexible random coil.
[2]
structurepLDDT=88.7 in the complex indicates the peptide adopts a well-defined structure when bound to ACE.
details expand to inspect
full evidence table2 metrics
metricvaluetool
ipTM 0.7699784636497498 boltz-2
ranking score 0.8633783459663391 boltz-2
structural qualityopenfold3
metricvaluenote
gpde1.101global PDE — lower = better
disorderNaNfraction disordered
3-letter notation
Glu-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro
recipeboltz-2 1.0
parametervalue
modelboltz-2 1.0
weights
hardwarenvidia_nim_api
mlx version
python
random seed
msa strategynone
diffusion samples1
runtime
predicted bymlx@peptide
predicted at2026-04-24
citationbibtex
peptidemodel (2026). Bradykinin-potentiating peptide 12c (pep-04671, v1). PeptideModel. https://peptidemodel.com/card/pep-04671
@peptide{pep04671,
  sequence = {EWPRPQIPP},
  target   = {ace},
  author   = {peptidemodel},
  year     = {2026},
  status   = {bioassayed}
}
references 1 papers
discussion no comments
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