Identification of dual-function bovine lactoferrin peptides released using simulated gastrointestinal digestion

Lactoferrin (LF) is a good protein for producing various bioactive peptides, such as those with antimicrobial, immunomodulating, and antihypertensive activities. However, there is no report about a peptide from lactoferrin with both angiotensin I-converting enzyme inhibitory (ACEI) and anticoagulant activities. This study investigated the ACEI and anticoagulant activities of the lactoferrin hydrolysate (LFH) produced using simulated gastrointestinal digestion and identified the potential peptide with both activities, as well as studied its active mechanisms. Results indicated that the LFH showed ACEI activity with an IC50 value of 0.38 +/- 0.06 mg mL(-1). Moreover, LFH showed its anticoagulant activity by prolonging the thrombin time from 13.1 +/- 0.1 to 20.9 +/- 0.5 s at 20 mg mL(-1). Nano-scale liquid chromatography-quadrupole time-of-flight mass spectrometry analysis showed that a total of 73 peptides with 7-21 amino acid residues were identified from LFH. The peptide ENLPEKADRD was evaluated for both ACEI and anticoagulant activities. Moreover, the molecular docking results showed that this peptide had strong interactions with ACE and thrombin indicated by "-CDOCKER_Energy" scores of 207 and 171 kcal mol(-1), respectively. Twelve ACE amino acid residues interacted with the peptide by forming 13 H-bonds, 7 electrostatic interactions, and 4 hydrophobic interactions. Eight thrombin amino acid residues interacted with peptide ENLPEKADRD by forming 10 H-bonds, 4 electrostatic interactions, and 1 hydrophobic interaction. These results showed that LF may potentially be used as an ingredient in functional food products with both antihypertensive and anticoagulant activities.