Purification of a novel angiotensin I-converting enzyme (ACE) inhibitory peptide with an antihypertensive effect from loach (Misgurnus anguillicaudatus).
To isolate and characterize novel angiotensin I-converting enzyme (ACE) inhibitory peptide from loach (Misgurnus anguillicaudatus), six proteases, pepsin, α-chymotrypsin, bromelain, papain, alcalase, and Neutrase, were used to hydrolyze loach protein. The hydrolysate (LPH) generated by bromelain [ratio of enzyme to substrate, 3:1000 (w/w)] was found to have the highest ACE inhibitory activity (IC(50), 613.2 ± 8.3 μg/mL). Therefore, it was treated by ultrafiltration to afford fraction of LPH-IV (MW < 2.5 kDa) with an IC(50) of 231.2 ± 3.8 μg/mL, having higher activity than the other fractions. Then, LPH-IV was isolated and purified by consecutive purification steps of gel filtration chromatography and reverse-phase high-performance liquid chromatography to afford a purified peptide with an IC(50) of 18.2 ± 0.9 μg/mL, an increase of 33.7-fold in ACE inhibitory activity as compared with that of LPH. The purified peptide was identified as Ala-His-Leu-Leu (452 Da) by Q-TOF mass spectrometry and amino acid analyzer. An antihypertensive effect in spontaneously hypertensive rats revealed that oral administration of LPH-IV could decrease systolic blood pressure significantly.
College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China.
Ying
Y
Li
Jianzhong
J
Zhou
Kaihong
K
Huang
Yi
Y
Sun
Xiaoxiong
X
Zeng
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D003531:Cypriniformes; D029941:Fish Proteins / Q000737:chemistry; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008297:Male; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D011492:Protein Hydrolysates / Q000737:chemistry / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats; D011918:Rats, Inbred SHR
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D029941:Fish Proteins; D010455:Peptides; D011492:Protein Hydrolysates