Structural analysis of a new anti-hypertensive peptide (beta-lactosin B) isolated from a commercial whey product.
Angiotensin-converting enzyme (ACE) inhibitory activities and anti-hypertensive activities in spontaneously hypertensive rats (SHR) of 12 kinds of commercial peptides of food additive grade were measured. Four peptide products derived from milk proteins showed strong anti-hypertensive activities (>-18.0 mm Hg). A sample of WE80BG derived from whey proteins showed the strongest anti-hypertensive activity (-21.2 +/- 16.9 mm Hg) with a medium level of ACE inhibitory activity (53.6%), and it was subjected to hydrophobic and gel filtration chromatography. From the low molecular weight fraction, an anti-hypertensive peptide was isolated by using reversed-phase HPLC, and it was found to be a tetrapeptide, alanine-leucine-proline-methionine (Ala-Leu-Pro-Met, ALPM), the origin of which was estimated to be beta-lactoglobulin f 142 to 145. At 8 h after oral administration of ALPM in SHR, systolic blood pressure was significantly decreased (-21.4 +/- 7.8 mm Hg), but the IC50 value (concentration of peptide needed to inhibit 50% of the ACE activity) of ALPM was not so high. We named the Ala-Leu-Pro-Met "beta-lactosin B." This peptide is the second anti-hypertensive peptide found from beta-lactoglobulin. Because WE80BG containing ALPM was also found to show the strongest anti-hypertensive activity (-24.5 +/- 10 mm Hg) at 8 h after oral administration in SHR, WE80BG would be suitable for application to the development of a new food expected to have anti-hypertensive effects.
Laboratory of Animal Products Chemistry, Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori - Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
M
M
Murakami
H
H
Tonouchi
R
R
Takahashi
H
H
Kitazawa
Y
Y
Kawai
H
H
Negishi
T
T
Saito
D000596:Amino Acids / Q000032:analysis; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D001794:Blood Pressure; D002851:Chromatography, High Pressure Liquid; D007700:Kinetics; D007782:Lactoglobulins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D008297:Male; D008894:Milk Proteins / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D000067816:Whey Proteins
C492389:Ala-Leu-Pro-Met; D000596:Amino Acids; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D007782:Lactoglobulins; D008894:Milk Proteins; D010446:Peptide Fragments; D010455:Peptides; D000067816:Whey Proteins