Optimal designing of β-conglycinin to genetically incorporate RPLKPW, a potent anti-hypertensive peptide

Modification of the amaranth 11S globulin storage protein to produce an inhibitory peptide of the angiotensin I converting enzyme, and its expression in Escherichia coli

“…Nevertheless, there are some studies, where peptides with antihypertensive and hypocholesterolemic properties have been inserted in the extension region of the a'-subunit of beta-conglycinin (Onishi et al, 2004;Nishizawa et al, 2008). However, all three subunits of beta-conglycinin, without any modification, have shown allergenicity in humans, sometimes with very strong reactions (Curciarello et al, 2008;Holzhauser et al, 2009;Krishnan et al, 2009).…”

“…Moreover, amaranth seed has been widely consumed since Aztec times and no allergenicity has been observed in consumers. We have targeted the genetically variable region III of an 11S globulin for the first time, and showed that the incorporation of four Val-Tyr peptides in tandem leads to a higher antihypertensive effect than attained previously (Onishi et al, 2004;Nishizawa et al, 2008).…”

Accumulation of the Bioactive Peptides, Novokinin, LPYPR and Rubiscolin, in Seeds of Genetically Modified Soybean

“…We have previously used the 0 subunit of -conglycinin (CG 0 ), one of the major storage proteins of soybean seeds, as a carrier protein for novokinin, with the peptide being incorporated into CG 0 at four sites by minimum replacement of the amino acids constituting analogous sequences. 9) An oral administration of transgenic soybean seeds that accumulated the modified protein, designated 4novokinin-0 , resulted in a reduction in the systemic blood pressure of spontaneously hypertensive rats. 10) This strategy is laborious, however, and it is therefore important to identify the substitution sites of carrier proteins suitable for the incorporation of different bioactive peptides.…”

“…To facilitate the release of novokinin from the carrier protein by digestive enzymes in the intestines, we inserted arginine and glutamine residues at the ends of each tandem repeat. 1,9) Trypsin predominantly cleaves proteins at the carboxyl side of lysine and arginine, except when either is followed by proline. In addition, chymotrypsin cleaves peptides at the carboxyl side of tyrosine, tryptophan, and phenylalanine.…”

“…Furthermore, we have previously elucidated that the addition of glutamine at the carboxyl side of tryptophan enhanced the release of a novokinin peptide. 9) Therefore, trypsin and chymotrypsin would be able to cleave RjRPLKPWjQ (j indicates the cleavage site) to release the novokinin. We also replaced site A of CG 0 with seven tandem repeats of LPYPR to generate Tr7LPYPR-0 (Fig.…”