Obestatin
23-amino acid gastric peptide derived from the ghrelin precursor, initially proposed as an anorexigenic hormone.
Chemical Identity
| Property | Value |
|---|---|
| Chemical Formula | C113H183N35O35 |
| Molecular Weight | 2516 Da |
| Peptide Class | Gastric Peptide (23 amino acids) |
| Sequence | FNAPFDVGIKLSGAQYQQHGRAL-NH2 |
| Processing | Cleaved from preproghrelin |
Structure
Obestatin is a 23-amino acid C-terminally amidated peptide derived from the preproghrelin precursor by proteolytic processing. It shares the same gene as ghrelin but is cleaved at a different site. The C-terminal amidation is essential for biological activity.
Mechanism of Action
Obestatin was initially reported to activate GPR39 and oppose ghrelin’s orexigenic effects, reducing food intake and body weight. However, subsequent studies have questioned these findings, and the receptor and physiological role remain controversial. It may have roles in water intake regulation and memory.
Clinical Applications
- Research interest: Potential satiety signal
- Ghrelin-obestatin ratio: Proposed biomarker for metabolic disorders
- Obesity: Controversial role in energy balance
- Memory: Potential cognitive effects
Pharmacology
- Controversy: Original findings not consistently reproduced
- Receptor: GPR39 identification debated
- Processing: Alternative cleavage of preproghrelin
- Distribution: Stomach, intestine, brain
References
- Zhang, J.V., et al. (2005). Obestatin: a peptide encoded by the ghrelin gene that opposes ghrelin. Science, 310, 996-999.
- Gourcerol, G., & Tache, Y. (2007). Obestatin: a ghrelin-associated peptide that does not hold its promise. Peptides, 28, 1377-1386.
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