Antihypertensive effects of lactoferrin hydrolyzates: Inhibition of angiotensin- and endothelin-converting enzymes

摘要

Departamento de Biotecnoiogia de Alimentos, Institute it Agroqulmica y Tecnologia de Alimentos, Consejo Superior de Investigations Cientificas (CS1C), Ave. Agustin Escardino 7, 46980 Paterna, Valencia, Spain;Centra de Investigation, Hospital Universitario 'La Fe', Ave. Campanar21, 46009 Valencia, Spain,Departamento de Fisiobgia, Universidad de Valencia, Ave. Blasco lbanez 17, 46010 Valencia, Spain,Unidad Mixta de Investigacidn Cerebrovascular, Fundacion Investigacidn Hospital La Fe - Universidad de Valencia, Valencia, Spain;Institute de Investigacidn en Ciencias de la Alimentaclon, CIAL, Consejo Superior de Investigations Cientificas-Universidad Autonoma de Madrid (CSIC-UAM). Nicolas Cabrera 9,28049 Madrid, Spain;Departamento de Biotecnoiogia de Alimentos, Institute it Agroqulmica y Tecnologia de Alimentos, Consejo Superior de Investigations Cientificas (CS1C), Ave. Agustin Escardino 7, 46980 Paterna, Valencia, Spain;Institute de Investigacidn en Ciencias de la Alimentaclon, CIAL, Consejo Superior de Investigations Cientificas-Universidad Autonoma de Madrid (CSIC-UAM). Nicolas Cabrera 9,28049 Madrid, Spain;Departamento de Biotecnoiogia de Alimentos, Institute it Agroqulmica y Tecnologia de Alimentos, Consejo Superior de Investigations Cientificas (CS1C), Ave. Agustin Escardino 7, 46980 Paterna, Valencia, Spain;%The potential of bovine lactoferrin (LF) as a source of antihypertensive peptides acting on the renin-angiotensin system (RAS) and the endothelin (ET) system as dual vasopeptidase inhibitors has been examined. For this purpose enzymatic LF hydrolyzates (LFHs) were generated by trypsin and proteinase K digestions. Permeate fractions with molecular masses lower than 3 kDa (LFH <3 kDa) were orally administered to spontaneously hypertensive rats (SHRs). Although both LFHs <3 kDa showed in vitro angiotensin I-converting enzyme (ACE)-inhibitory activity, only proteinase K LFH <3 kDa exerted an in vivo antihypertensive effect. The proteinase K LFH <3 kDa and a previously characterized pepsin LFH <3 kDa with ACE-inhibitory and antihypertensive effects were tested in ex vivo functional assays as inhibitors of ACE-dependent vasoconstriction. Pepsin LFH <3 kDa but not proteinase K LFH <3 kDa inhibited ACE-dependent vasoconstriction. When tested as inhibitors towards endothelin-converting enzyme (ECE), both LFHs <3 kDa exerted in vitro inhibitory effects on ECE activity and inhibited ECE-dependent vasoconstriction. Most abundant peptides in proteinase K LFH <3 kDa were identified by using an ion trap mass spectrometer. Based on peptide abundance, two peptides (GILRPY and REPYFGY) were chemically synthesized and their ECE-inhibitory activity was tested. Both exerted in vitro inhibitory effects on ECE activity. In conclusion, orally effective antihypertensive LFHs <3 kDa may act as dual vasopeptidase (ACE/ECE) or as single ECE inhibitors with different antivasoconstrictor effects depending on the protease used to release bioactive peptide sequences.