caa a22 4500 397557728 CHVBK 20180308164807.0 cr unu---uuuuu 161202e199605 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a021324 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a021324 Chymotrypsin Inhibition Induced by Side Chain-Side Chain Intramolecular CH/Φ Interaction in D-Thr-L-Phe Benzylamide [Elektronische Daten] [Iori Maeda, Yasuyuki Shimohigashi, Koichi Ikesue, Takeru Nose, Yuzuru Ide, Keiichi Kawano, Motonori Ohno] The dipeptide benzyl amide H-D-Thr-Phe-NH-CH2-C6H5 was found to inhibit chymotrypsin strongly (K1=4.5×lO−5M) in a competitive manner. When a series of phenyl amides H-D-Thr-Phe-NH-(CH2;)n;-C6;H5 (n = 0-4) were tested, inhibitory potency peaked at n = l (benzyl amide). Incorporation of a methyl group into the benzyl methylene resulted in formation of stereoisomers, H-D-Thr-Phe-NH-(R or S)-CH(CH3)-C6H5, with considerably different inhibitory potencies. The JZ-isomer was as active as the benzyl amide, while the S-isomer was about 30-fold less active than the benzyl amide. Furthermore, when a fluorine atom was introduced into the para-position of the amide-benzyl group, the resulting inline;; showed considerably enhanced inhibitory activity (about 5-fold, K=9.1×1O−10M). In conformational analysis by 400 mHz 'H-NMR, all dipeptides having D-Thr-Phe backbone structure showed large upfield shifts of D-Thr-Oi? (shifts in ppm, 0.09-0.17), D-Thr-βCG (0.23-0.32), and D-Thr-γCH3 (0.38-0.63), indicating the presence of shielding effects from the benzene ring. In addition, NOE enhancements between the D-Thr- βCH3 and Phe-phenyl groups were evidenced by measurements of two-dimensional NOESY spectra and NOE difference spectra. These observations demonstrated the spatial proximity of these side chains, which is due to side chain-side chain CH/π interaction. All these results support the idea that the amide-benzyl group binds at the chymotrypsin S1, site, while the hydrophobic core with CH/π interaction binds at the S2 or S1,' site. © by the Journal of Biochemistry Regular Papers nationallicence CH/π interaction nationallicence chymotrypsin nationallicence dipeptide inhibitor nationallicence enzyme inhibitor nationallicence inhibitory conformation nationallicence Maeda Iori Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut Shimohigashi Yasuyuki Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut Ikesue Koichi Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut Nose Takeru Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut Ide Yuzuru Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut Kawano Keiichi Division of Biological Sciences, Graduate School of Science, Hokkaido University Sapporo 060 aut Ohno Motonori Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut The Journal of Biochemistry Oxford University Press 119/5(1996-05), 870-877 0021-924X 119:5<870 1996 119 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a021324 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a021324 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Maeda Iori Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut NATIONALLICENCE 700 1- Shimohigashi Yasuyuki Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut NATIONALLICENCE 700 1- Ikesue Koichi Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut NATIONALLICENCE 700 1- Nose Takeru Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut NATIONALLICENCE 700 1- Ide Yuzuru Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut NATIONALLICENCE 700 1- Kawano Keiichi Division of Biological Sciences, Graduate School of Science, Hokkaido University Sapporo 060 aut NATIONALLICENCE 700 1- Ohno Motonori Laboratory of Biochemistry, Department of Chemistry, Faculty of Science, Kyushu University Fukuoka 812-81 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 119/5(1996-05), 870-877 0021-924X 119:5<870 1996 119 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford