Nanomolar ACE-Inhibitory Peptide From Chlorella Algae Shows Blood Pressure Reduction In Vivo With Novel Binding Mechanism
Starting from 99 peptides identified in Chlorella pyrenoidosa hydrolysate, researchers optimized a lead peptide to discover LR-5 (LRAKA), a novel nanomolar ACE inhibitor (IC50: 350 nM) that lowered blood pressure in vivo and binds ACE at an unconventional site.
Quick Facts
What This Study Found
99 peptides identified from Chlorella by LC-MS/MS. LVAKA (LV-5) IC50: 26.66 μM for ACE inhibition. Three peptides (LV-5, LKKAP, PGLRP) stable at extreme pH and temperature. Sequence optimization yielded LRAKA (LR-5): nanomolar ACE inhibition (IC50: 350 nM in vitro) and in vivo blood pressure reduction in rats. LR-5 binds an unconventional ACE site.
Key Numbers
99 peptides identified by LC-MS/MS. 10 selected by virtual screening. Lead peptide showed nanomolar ACE inhibition.
How They Did This
Trypsin hydrolysis of Chlorella pyrenoidosa. LC-MS/MS peptide identification (99 peptides). Virtual screening by molecular docking. In vitro ACE inhibition assays. Stability testing under pH/temperature extremes and simulated gastrointestinal digestion. Sequence optimization. In vivo blood pressure testing in rats. Molecular dynamics simulation for binding mechanism.
Why This Research Matters
Most food-derived ACE-inhibitory peptides have micromolar potency, limiting practical utility. LR-5's nanomolar potency is exceptional — approaching pharmaceutical-grade activity. Combined with digestive stability and in vivo blood pressure reduction, this represents one of the most promising food-derived antihypertensive peptides discovered.
The Bigger Picture
A nanomolar food-derived ACE inhibitor that survives digestion and works in vivo bridges the gap between functional foods and pharmaceuticals. Chlorella is already commercially produced at scale, making this a potentially viable source of natural antihypertensive ingredients.
What This Study Doesn't Tell Us
Animal study (rats) for in vivo validation — human blood pressure data needed. The optimization from LV-5 to LR-5 creates a semi-synthetic peptide, not purely 'natural.' Oral bioavailability in humans not confirmed. Single animal study may not reflect clinical efficacy.
Questions This Raises
- ?Could LR-5 be developed as a pharmaceutical antihypertensive peptide drug, or is it better suited as a nutraceutical?
- ?What is the significance of the unconventional ACE binding site — does it predict different clinical effects than standard ACE inhibitors?
- ?Is LR-5 absorbed intact from the human gut at bioactive concentrations?
Trust & Context
- Key Stat:
- IC50: 350 nM The optimized peptide LR-5 inhibits ACE at nanomolar concentrations — approximately 76 times more potent than the original lead peptide and approaching pharmaceutical-grade activity from a food source
- Evidence Grade:
- Rated preliminary: impressive in vitro potency with in vivo blood pressure confirmation in rats. However, no human clinical data. The sequence optimization step means this is not purely a 'natural' food peptide.
- Study Age:
- Published in 2024. At the forefront of bioactive peptide optimization from microalgae sources.
- Original Title:
- Discovery of a novel nanomolar angiotensin-I converting enzyme inhibitory peptide with unusual binding mechanisms derived from Chlorella pyrenoidosa.
- Published In:
- International journal of biological macromolecules, 280(Pt 2), 135873 (2024)
- Authors:
- Suo, Qishan(2), Wang, Jing(11), Wu, Ning(3), Geng, Lihua, Zhang, Quanbin, Yue, Yang
- Database ID:
- RPEP-09349
Evidence Hierarchy
Frequently Asked Questions
Can algae-derived peptides really lower blood pressure?
This study found a remarkably potent one. Starting from Chlorella (a common health food supplement), researchers discovered and optimized a peptide called LR-5 that inhibits the same enzyme targeted by blood pressure medications — at concentrations approaching drug-level potency (350 nanomolar). It also lowered blood pressure in rats, but human studies are still needed.
How does this compare to blood pressure medications?
LR-5's nanomolar potency is unusually strong for a food-derived peptide and approaches the range of pharmaceutical ACE inhibitors. It also binds ACE at an unusual site, which could mean different effects than standard drugs. However, food-derived peptides face challenges with absorption and bioavailability that drugs have already solved.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-09349APA
Suo, Qishan; Wang, Jing; Wu, Ning; Geng, Lihua; Zhang, Quanbin; Yue, Yang. (2024). Discovery of a novel nanomolar angiotensin-I converting enzyme inhibitory peptide with unusual binding mechanisms derived from Chlorella pyrenoidosa.. International journal of biological macromolecules, 280(Pt 2), 135873. https://doi.org/10.1016/j.ijbiomac.2024.135873
MLA
Suo, Qishan, et al. "Discovery of a novel nanomolar angiotensin-I converting enzyme inhibitory peptide with unusual binding mechanisms derived from Chlorella pyrenoidosa.." International journal of biological macromolecules, 2024. https://doi.org/10.1016/j.ijbiomac.2024.135873
RethinkPeptides
RethinkPeptides Research Database. "Discovery of a novel nanomolar angiotensin-I converting enzy..." RPEP-09349. Retrieved from https://rethinkpeptides.com/research/suo-2024-discovery-of-a-novel
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.