The ACE inhibitory activity and fibroblast proliferation of collagen peptides: Comparing amino acid composition and sequence

This study compared the degree of hydrolysis, peptide sequences, angiotensin-converting enzyme (ACE) inhibitory activity, and fibroblast proliferation activity of collagen derived from fish skin, pig skin, and bovine bone. The amino acid composition revealed that fish skin collagen had the lowest hydroxyproline content, while bovine bone collagen had the highest. Bovine bone collagen peptides contained a greater number of sequences with proline at the C-terminus, whereas fish and pig skin collagen peptides had a higher percentage of sequences containing PO and GPO, at 47.2 ​% and 55.2 ​%, respectively. Peptide sequences may determine the functional variability of collagen peptides from different sources: bovine bone collagen peptides exhibited the highest ACE inhibitory activity, with an IC50 value of 1.5 ​mg/mL; the fish skin and pig skin collagen peptide groups increased fibroblast proliferation rates by 139.1 ​% and 149.5 ​%, respectively, and cell migration rates by 19.3 ​% and 22.1 ​%, respectively; furthermore, fibroblasts showed the most significant enhancement in proline and hydroxyproline synthesis after treatment with pig skin collagen peptides. These results indicate that Pig and fish skin collagen peptides are more effective in promoting proliferation, migration, and collagen synthesis, which provides important guidance for selecting optimal collagen sources based on specific functional requirements. • Bovine bone collagen peptides had most hydroxyproline and proline at the C-terminal. • Fish and pig skin collagen peptides had a higher percentage of sequences with PO and GPO. • Bovine bone collagen peptides demonstrating the highest ACE inhibitory activity. • Pig and fish skin collagen peptides showed greater efficacy in promoting collagen synthesis.