N methylmorpholine

All 9-fluorenylmethyloxycarbonyl (Fmoc)-labeled amino acids and resin-bound amino acids were purchased from Watanabe Kagaku (Hiroshima, Japan). Piperidine for eliminating Fmoc during peptide synthesis was purchased from Tokyo Chemical Industry (Tokyo, Japan). N-Methylmorpholine and 1, 2-ethanedithiol were purchased from Nacalai Tesque (Kyoto, Japan). HPLC-grade acetonitrile, N, N-dimethylformamide, diethyl ether, trifluoroacetic acid, thioflavin T, and 4,4′-dianilino-1,1′-binaphthyl-5,5′-disulfonic acid (Bis-ANS) were purchased from Sigma Aldrich (St. Louis, MO, USA). Recombinant human protein-L-isoaspartate O-methyltransferase was purchased from NKMAX (Seongnam-si, Republic of Korea). All other analytical chemicals were purchased from FUJIFILM Wako Pure Chemical Industries (Osaka, Japan).

EGCG was purchased from Bio Verde Inc. (Kyoto, Japan), N-methylmorpholine (NMM) was purchased from Nacalai Tesque Inc. (Kyoto, Japan), 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methyl-morpholinium chloride (DMT-MM) was purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan), and type A gelatin from porcine skin was acquired from Sigma-Aldrich (St. Louis, MO, USA).