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Mung bean is a well-known good source of protein. To increase its bioactivity, economic value, and nutritional content as a functional food and food additive, lactostatin (IIAEK), a cholesterol-lowering bioactive peptide, was engineered into mung bean 8Sα globulin, a major storage protein. The results showed that the mutated 8Sα globulin has a significant bile acid binding capacity (cholesterol-lowering activity) up to 47.25%. Moreover, superimposed mutant (Mut2) and wild-type (Wt) 3D protein structures showed a 93–97% identity, indicating that the mutant proteins are stable. Ultra-performance liquid chromatography(UPLC)-based assay showed similar retention time for wild-type and mutant protein samples. Both IIAEK peptide standard and Mut2 digest had comparable baseline peaks corresponding to the same molecular size based on the liquid chromatography-mass spectrometry (LC-MS) data. A 573.36-Da mass spectrum was seen in Mut2, which indicates that Mut2 8Sα globulin has been successfully mutated and digested to release the bioactive peptide, IIAEK. In vitro bile acid binding capacity showed that the 6-h Wt and 12-h engineered protein (Mut2) digests had the highest activity. Lastly, potential allergenicity was checked in the Allergen Database for Food Safety (ADFS) and the AllerBase database, and the IIAEK peptide matched the Bos d 5 epitopes. This study provides a strong foundation and basis for mung bean nutrition improvement, development of cholesterol-lowering food supplements, and protein engineering of other food proteins. [ABSTRACT FROM AUTHOR]

Mung bean is a well-known good source of protein. To increase its bioactivity, economic value, and nutritional content as a functional food and food additive, lactostatin (IIAEK), a cholesterol-lowering bioactive peptide, was engineered into mung bean 8Sα globulin, a major storage protein. The results showed that the mutated 8Sα globulin has a significant bile acid binding capacity (cholesterol-lowering activity) up to 47.25%. Moreover, superimposed mutant (Mut2) and wild-type (Wt) 3D protein structures showed a 93–97% identity, indicating that the mutant proteins are stable. Ultra-performance liquid chromatography(UPLC)-based assay showed similar retention time for wild-type and mutant protein samples. Both IIAEK peptide standard and Mut2 digest had comparable baseline peaks corresponding to the same molecular size based on the liquid chromatography-mass spectrometry (LC-MS) data. A 573.36-Da mass spectrum was seen in Mut2, which indicates that Mut2 8Sα globulin has been successfully mutated and digested to release the bioactive peptide, IIAEK. In vitro bile acid binding capacity showed that the 6-h Wt and 12-h engineered protein (Mut2) digests had the highest activity. Lastly, potential allergenicity was checked in the Allergen Database for Food Safety (ADFS) and the AllerBase database, and the IIAEK peptide matched the Bos d 5 epitopes. This study provides a strong foundation and basis for mung bean nutrition improvement, development of cholesterol-lowering food supplements, and protein engineering of other food proteins.

Elevated concentrations of cholesterol in plasma are associated with increased risk for heart diseases in humans. Bioactive peptides can be considered as an option to prevent or treat this condition. Currently, there are wide sources of bioactive peptides with hypocholesterolemic activities; however, most researches are focused in bioactive peptides derived from soybean and milk protein. Although there are several preparation methods for these peptides, it is a novel process to prepare bioactive peptides by genetic engineering techniques. In this review, after a general introduction on approaches and advances in bioactive peptides, recombinant strategies to generate hypocholesterolemic peptides and their purification are discussed as well as their application in food and drug design. [ABSTRACT FROM AUTHOR]

Hypercholesterolemia, a form of cardiovascular disease, is one of the leading causes of deaths worldwide. Lactostatin (Ile-Ile-Ala-Glu-Lys), derived from β-lactoglobulin in cow's milk, is a bioactive peptide with hypocholesterolemic activity higher than sitosterol, a known anti-hypercholesterolemic drug. Here, we successfully developed a transgenic rice accumulating a much higher level of lactostatin by inserting 29 IIAEK sequences into the structurally flexible (nonconserved) regions of soybean seed storage protein, A1aB1b, and introducing it into LGC-1 (low glutelin content mutant 1) as host variety. A1aB1b containing 29 lactostatins was expressed in the endosperm of rice seed cells by using seed specific promoters and sorted into novel compartments distinct from normal PB-I (ER-derived protein body) and PB-II (protein storage vacuoles). Transgenic rice seeds accumulated approximately 2 mg of lactostatins/g of dry seeds, which is relatively high compared with previous reports. Our findings suggest that the introduction of a high copy number of bioactive peptide into seed storage proteins as carrier is one of the effective means in producing higher amounts of bioactive peptides in rice. [ABSTRACT FROM AUTHOR]

Abstract: Our group previously discovered a novel hypocholesterolemic pentapeptide (IIAEK: Ile-Ile-Ala-Glu-Lys, or what we describe as “lactostatin”) derived from bovine milk β-lactoglobulin. To clarify the mechanism of the hypocholesterolemic action of lactostatin, we screened the target gene and signal transducing pathway induced by lactostatin in HepG2, a human liver cell line. Unexpectedly, we found that water-soluble lactostatin can activate cholesterol 7α-hydroxylase (CYP7A1) gene expression. Treatment with mitogen-activated protein kinase (MAPK) inhibitor or calcium (Ca2+) channel blocker blocked this activation. We also found that lactostatin regulates the phosphorylation of extracellular signal-regulated kinase (ERK) and intracellular Ca2+ concentration. Here, we show the involvement of a new regulatory pathway in the calcium-channel-related MAPK signaling pathway of lactostatin-mediated cholesterol degradation. Oligopeptide shows promise as a new molecule for the development of medicines and functional foods to prevent and improve hypercholesterolemia and atherosclerosis. [Copyright &y& Elsevier]

This review addresses the structure–function properties of hypolipidemic peptides. The cholesterol‐lowering peptide (lactostatin: IIAEK) operates via a new regulatory pathway in the calcium‐channel‐related mitogen‐activated protein kinase (MAPK) signaling pathway of cholesterol degradation. The bile acid binding peptide (soystatin, VAWWMY) inhibits the micellar solubility of cholesterol in vitro and cholesterol absorption in vivo. VVYP is the most effective peptide having hypotriglyceridemic action in globin digests. The suppressive effect of globin digest on postprandial hyperlipidemia has been reported in humans. The ability of peptides (KRES, Apolipoprotein A‐I mimetic peptides) to interact with lipids, remove LOOH and activate antioxidant enzymes associated with high‐density lipoprotein determines their anti‐inflammatory and anti‐atherogenic properties. The β‐conglycinin derived peptides KNPQLR, EITPEKNPQLR, and RKQEEDEDEEQQRE inhibit fatty acid synthase in vitro. These promising findings indicate the need for more conclusive molecular, cellular, and animal and human studies to design innovative new peptides that ameliorate cholesterol and lipid metabolism. Practical applications: Prevention and amelioration of hypercholesterolemia by dietary regulation are important. Dietary protein and peptides are very useful as regulators of serum cholesterol concentration. Diets low in saturated fat and cholesterol that include soy protein may reduce the risk of heart disease. In Japan, the concept of "food for specified health use" has been introduced for the prevention and treatment of life‐style related disease. Thus, peptides derived from food proteins and sources other than food proteins such as peptide‐rich functional foods and nutraceutical products, have considerable potential to prevent lifestyle‐related diseases, especially hyperlipidemia, as discussed in this review. Furthermore, various strategies have been used for the efficient screening, development, and application of new hypolipidemic peptides. These include the use of phage display (for anti‐obesity peptide), peptide mimetics (for anti‐atherogenic peptide), and molecular targets such as CYP7A1 (for hypocholesterolemic peptide) and prohibitin (for anti‐obesity peptide). [ABSTRACT FROM AUTHOR]