Purification and characterization of an angiotensin I‐converting enzyme inhibitory peptide derived from porcine troponin C

Abstract

To search for a novel angiotensin I‐converting enzyme (ACE) inhibitory peptide, porcine skeletal troponin was hydrolyzed with pepsin. This hydrolysate showed ACE inhibitory activity, and was applied to various kinds of chromatography to separate an active peptide. Analysis using a protein sequencer identified this peptide as RMLGQTPTK (9mer). This sequence was estimated to occur at the 44–52 position of troponin C, and its 50% inhibitory protein concentration (IC50) was 34 µM. RMLGQTP (7mer), a partial peptide of 9mer, showed activity with an IC50 of 503 µM. RP‐HPLC analysis of a reaction mixture of 9mer and ACE showed that 9mer was slowly hydrolyzed by ACE. On the other hand, 7mer was rapidly hydrolyzed by ACE. Activity of 9mer was reduced as its hydrolysis by ACE proceeded. To estimate the resistance of 9mer to digestive proteases after oral administration, it was reacted with pepsin, α‐chymotrypsin, or trypsin. In each of these reaction mixtures, a significant amount of 9mer remained as a substrate after digestion. Remaining ACE inhibitory activity was close to that of 9mer. These results suggest that 9mer might not be digested after oral administration, because of its relatively high resistance to digestive proteases. Therefore, 9mer might be expected to work well in vivo as an ACE inhibitor.

Angiotensin‐I Converting Enzyme Inhibitory Peptide Derived from Porcine Skeletal Muscle Myosin and Its Antihypertensive Activity in Spontaneously Hypertensive Rats

“…This peptide was synthesized for subsequent researches and its IC 50 was 28.5 μM. It was higher than those of peptides derived from myosin heavy chain (Met‐Asn‐Pro‐Pro‐Lys and Ile‐Thr‐Thr‐Asn‐Pro) (Arihara and others 2001), and peptides from troponin C (Arg‐Met‐Leu‐Gly‐Gln‐Thr‐Pro‐Thr‐Lys) (Katayama and others 2003a). …”

“…Antihypertensive activity of peptides derived from porcine myosin in spontaneously hypertension rat (SHR) was also investigated, and hydrolysate of porcine myosin and peptides showed antihypertensive activity on SHR (Nakashima and others 2002). Purification and characterization of ACE inhibitory peptide derived from porcine troponin C were successfully investigated, and an ACE inhibitory peptide was identified as Arg‐Met‐Leu‐Gly‐Gln‐Thr‐Pro‐Thr‐Lys (Katayama and others 2003a). The concentration of this nonapeptide necessary to inhibit 50% (IC 50 ) activity of ACE in vitro was 34 μM.…”

Purification of Angiotensin Converting Enzyme Inhibitory Peptide Derived From Kacang Goat Meat Protein Hydrolysate

“…Antihypertensive activity of peptides derived from porcine myosin in spontaneously hypertension rat (SHR) was also investigated, and hydrolysate of porcine myosin and peptides showed antihypertensive activity on SHR (Nakashima et al, 2002). Purification and characterization of ACE inhibitory peptide derived from porcine troponin C were successfully investigated, and an ACE inhibitory peptide was identified as Arg-Met-Leu-Gly-GlnThr-Pro-Thr-Lys (Katayama et al, 2003a). The concentration of this nonapeptide necessary to inhibit 50% (IC50) activity of ACE in vitro was 34 mM.…”

Mung-bean Protein Hydrolysates Obtained with Alcalase Exhibit Angiotensin I-converting Enzyme Inhibitory Activity

“…Alcalase, a food grade enzyme, is also advantageous with low cost with respect to its industrialised production when compared with pepsin, trypsin, chymotrypsin, papain and thermolysin, which have also been used for the preparation of ACE inhibitory peptides from food proteins (Mullally et al, 1997;Arihara et al, 2001;Katayama et al, 2003).…”