Related Experiment Video
Updated: Aug 13, 2026
Quantification of Hypopigmentation Activity In Vitro
Published on: March 6, 2019
Identification of a melanocyte growth-inhibiting tripeptide and determination of its structure
D S Gembitsky1, K L Reichelt, P Haakonsen
1Institute of Pathology, University of Oslo, The National Hospital (Rikshospitalet), Norway.
Abstract:
The function and proliferation of melanocyte cell populations are influenced by a wide range of hormones and growth factors. Local cell renewal after sudden melanocyte loss appears to be regulated according to a negative feedback principle, however. In accordance with this assumption, we have examined growth-inhibitory activity in water extracts of cultured non-transformed melanocytes and melanoma cells (B16 cells). The extracts were fractionated by gel filtration on Sephadex G-25 and Fractogel MG 2000, by ion-exchange chromatography on DEAE-cellulose and Dowex 50 and by reverse-phase high-performance liquid chromatography on Bondesil and Partisil columns. Two peptides were isolated with the structures pyroGlu-Phe-GlyNH2 and pyroGlu-Cys-GlyNH2 as revealed by mass spectrometry, peptide sequencing and amino acid analysis. The two peptides were synthesized and tested for the ability to inhibit the growth of melanocyte cultures. Only pyroGlu-Phe-GlyNH2 was inhibitory. The dose-response curve was bell-shaped with maximum inhibition around 10(-15) M. The melanocyte tripeptide thus appears to be a new member of a group of N-substituted growth-regulating oligopeptides found in other tissues.
Insights
Researchers identified a new tripeptide, pyroGlu-Phe-GlyNH2, that inhibits melanocyte growth. This peptide may play a role in regulating cell renewal through a negative feedback mechanism.
Area of Science:
- Cell Biology
- Biochemistry
- Peptide Research
Background:
- Melanocyte function and proliferation are regulated by hormones and growth factors.
- Local melanocyte renewal suggests a negative feedback mechanism for cell population control.
Purpose of the Study:
- To investigate growth-inhibitory activity in melanocyte extracts.
- To isolate and characterize peptides involved in melanocyte growth regulation.
Main Methods:
- Water extracts from cultured melanocytes and melanoma cells were analyzed.
- Peptide isolation using gel filtration, ion-exchange, and reverse-phase HPLC.
- Peptide structure determination via mass spectrometry, sequencing, and amino acid analysis.
Main Results:
- Two peptides, pyroGlu-Phe-GlyNH2 and pyroGlu-Cys-GlyNH2, were isolated.
- Only pyroGlu-Phe-GlyNH2 demonstrated significant melanocyte growth inhibition.
- The inhibition showed a bell-shaped dose-response curve, with maximal effect at 10(-15) M.
Conclusions:
- PyroGlu-Phe-GlyNH2 is a novel melanocyte-inhibitory tripeptide.
- This peptide represents a new class of N-substituted oligopeptides regulating tissue growth.
- It may be a key component of the negative feedback system controlling melanocyte populations.
