Nippi Corporation

Japan Institute of Leather Research

Masashi Kusubata

Osamu Hayashida

Shunji Hattori

Yuki Taga

Yoh-ichi Koyama

Satoshi Suzuki

Shinkichi Irie

Koki Suzuki

Koki Ogata

Yuji Atsuzawa

Youichi Koyama

Yoh-Ichi Koyama

Provided are methods of producing a novel collagen peptide composition, and a DPP-4 inhibitor and antihyperglycemics that comprise the above-mentioned collagen peptide composition. Ginger rhizome-derived enzymes are added to and break down a collagen and/or gelatin solution to generate peptide compositions comprising peptides represented by X-Hyp-Gly (wherein X represents an amino acid residue other than Gly, Hyp, and Pro). The thus obtained collagen peptide composition has a high DPP-4 inhibitory activity and an excellent antihyperglycemic effect.

Collagen peptide composition production method, DPP-4 inhibitor, and antihyperglycemic agent

A DPP-4 inhibitor comprising a peptide represented by the formula (1): Xe-Pro/Ala/Hyp-Xa-Xb-Xc-Xd (SEQ ID NO: 16) (wherein Xe is an amino acid residue with an isoelectric point of 5.9 to 6.3; Pro/Ala/Hyp represents Pro, Ala, or Hyp; Xa is an amino acid residue other than Hyp, Pro, and Arg, or deletion; 5 Xb is Gly, Pro, or deletion; Xc is Pro, Ala, or deletion; and Xd is an amino acid residue or deletion) as an active component. The inhibitor can be expected to bring out an effect of lowering blood glucose levels by enhancing effects of incretins; and the inhibitor may be used as a therapeutic agent for diabetes and, in addition, can act on the immune system or the like to be thus used in 10 treatment for skin diseases or the like.

DPP-4 inhibitor

Large amounts of hairs and feathers can be decomposed and refined by treatment in an oxygen-containing gas stream with a fungus that can decompose hairs and feathers. The resulting decomposed and refined hairs and feathers are useful as a fertilizer.

Method of treating hairs or feathers using microorganisms

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Tokyo, Japan

Masashi Kusubata