Soybean protein fraction digested with neutral protease preparation, “Peptidase R”, produced by Rhizopus oryzae, stimulates innate cellular immune system in mouse

Abstract

A soybean protein fraction was prepared from defatted soybean seed flour and digested with 29 kinds of commercially available protease originating from preparations of animals, plants, and microorganisms. Some digests, in particular, Ro-digest prepared using a Rhizopus oryzae neutral protease preparation (Peptidase R), displayed strong

Fermented Soybean Powder with Rice Mold in the Absence of Salt Stimulates the Cellular Immune System and Suppresses the Humoral Immune Response in Mice

“…As mentioned in the Introduction section, we demonstrated that a glutamine-rich peptide derived of soybean protein fraction stimulates the cellular immune response in the mouse (3,4). Ito et al also reported that isoflavones in a fermented soybean product might modulate the immune systems and prevent liver cancer in the mouse (12).…”

Characterization of a Cellular Immunostimulating Peptide from a Soybean Protein Fraction Digested with Peptidase R

“…It is known that food components including bacteria penetrate the mucosal barrier via M cells, which endocytoses and transports the components into the Peyer's patches, and initiates immune responses (29). In our previous study (8), we demonstrated that the oral administration of Ro-digest stimulated the innate cellular immune systems in mice. The H1 in the Ro-digest is considered to remain unabsorbed from intestinal tracts because of its higher molecular mass (2549.18).…”

“…Moreover, DNA microarray analysis showed that the gene expression related to the innate immune response in Peyer's patch cells increased in mice given the diet ( 8 ). In this study, we characterized an immunostimulating peptide in the soybean protein fraction digested with Peptidase R (Ro-digest).…”

“…Preparation of Ro-digest . Ro-digest was prepared according to a previously described procedure ( 8 ). In brief, the acid-precipitated protein fraction was suspended in distilled water and boiled.…”

“…Yoshikawa et al ( 6 ) demonstrated that a peptide corresponding to residues 296 to 301 of the glycinin A1a subunit stimulated phagocytosis in mice, while Tsuruki et al ( 7 ) isolated a phagocytosis-stimulating peptide corresponding to residues 173 to 185 of the ␤ -conglycinin ␣ ′ subunit. In our previous study ( 8 ), we demonstrated that a peptide mixture obtained from an acid-precipitated soybean protein fraction digested with Peptidase R produced by Rhizopus oryzae displayed a strong mitogenic activity and increased the number of interleukin (IL)-12 …”