Two bioactive peptides isolated from shrimp head protein showed antibacterial activity against multiple pathogens and potent ACE inhibitory activity for blood pressure regulation.
IC50: 125.58 µMACE inhibitory activity of the peptide ARL/I, identified as a competitive inhibitor of the blood pressure-regulating enzyme
What the researchers found
After enzymatic hydrolysis and two rounds of chromatographic purification, researchers identified two key peptides from kuruma shrimp head protein. The antibacterial peptide VTVP showed minimum inhibitory concentration (MIC) values ranging from 1.62 to 8.03 mM against all tested pathogens. The ACE inhibitory peptide ARL/I demonstrated an IC50 value of 125.58 µM and was confirmed as a competitive inhibitor through Lineweaver-Burk analysis.
Molecular docking revealed that ARL/I binds to ACE primarily through hydrogen bonds and forms a coordinate bond with the zinc ion at the enzyme's active site. Importantly, neither peptide showed hemolytic activity against rabbit red blood cells, indicating a favorable safety profile.
Why it matters
Seafood processing generates enormous amounts of waste, including shrimp heads rich in protein. Finding valuable bioactive peptides in this waste stream addresses both sustainability concerns and the need for new antibacterial and blood pressure-lowering agents, particularly as antibiotic resistance grows.
How the study worked
Shrimp heads were hydrolyzed with papain enzyme at 50°C for 4 hours. The resulting protein hydrolysate was purified through two stages of reversed-phase high-performance liquid chromatography (RP-HPLC). Active peptides were identified using LC-MS/MS. Antibacterial activity was measured by minimum inhibitory concentration (MIC), ACE inhibition was assessed with IC50 values and kinetic analysis, and molecular docking simulations modeled peptide-enzyme interactions.
What this study cannot tell us
This was a laboratory study only — the peptides were not tested in living organisms for blood pressure reduction or infection treatment. The antibacterial testing was limited to a set of selected pathogens. Stability of these peptides during digestion and their bioavailability in the human body remain unknown.
How to read the evidence
This is an in vitro laboratory study with molecular docking simulations. While the peptide identification and characterization are rigorous, no animal or human trials were conducted, placing this at an early preclinical evidence level.
When this study was published
Published in 2023, this study represents recent work in the active field of food-derived bioactive peptides.
The bigger picture
This study contributes to the growing field of food-derived bioactive peptides, where researchers are mining protein-rich waste products for compounds with health benefits. ACE inhibitory peptides from food sources are of particular interest as potential natural alternatives or supplements to synthetic blood pressure medications.
Questions still open
- Would these peptides remain active after passing through the human digestive system?
- Could VTVP be developed into a natural food preservative for the seafood industry?
- How does the ACE inhibitory potency of ARL/I compare to established food-derived peptides like those from milk or fish?
Common questions
What are ACE inhibitory peptides and why do they matter?
Can eating shrimp heads provide these health benefits?
Read the original research
Preparation, Purification and Characterization of Antibacterial and ACE Inhibitory Peptides from Head Protein Hydrolysate of Kuruma Shrimp, Marsupenaeus japonicus.
Molecules (Basel, Switzerland), 28(2)
Citation
Zhou, Jie; Han, Qiuyu; Koyama, Tomoyuki; Ishizaki, Shoichiro. (2023). Preparation, Purification and Characterization of Antibacterial and ACE Inhibitory Peptides from Head Protein Hydrolysate of Kuruma Shrimp, Marsupenaeus japonicus.. Molecules (Basel, Switzerland), 28(2). https://doi.org/10.3390/molecules28020894