著者

黒田 雅利 島崎 智憲 岩本 達也 秋田 貢一 小林 祐次 水野 悠太

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.72, no.3, pp.154-160, 2023-03-15 (Released:2023-03-20)

参考文献数

13

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In order to develop the technique to predict the surface characteristics of fatigue specimens of austenitic stainless steels by controlling finishing processing of lathe turning and shot peening, the applicability of the response surface models formerly created by the present authors using experimental design of experiments approaches to the fatigue specimens with different types and/or rolling conditions of austenitic stainless steels have been investigated. The conclusive remarks could be summarized as follows: (1) The predicted surface residual stress obtained by the response surface model of the lathe turning created for the round bars of SUS304 agreed with the observed surface residual stress of the fatigue specimen of SUS316. (2) The response surface model of the shot peening created for the flat plate of SUS316 was applicable to the prediction of the surface roughness RSm, the surface hardness and the surface residual stress of the fatigue specimen of SUS316 in spite of the different processing of the shot peening and the rolling conditions of the material.

著者

泰地 美沙子 山崎 俊正 河原 一樹 元岡 大祐 中村 昇太 豊島 正 大久保 忠恭 小林 祐次 西内 祐二

出版者

天然有機化合物討論会実行委員会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

vol.53, pp.199-204, 2011

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Marinostatin (MST) isolated from a marine organism is a serine protease inhibitor consisting of 12 amino acids with two internal ester linkages formed between the β-hydroxyl and (β-carboxyl groups, Thr^3-Asp^9 and Ser^8-Asp^<11>. MST was synthesized by regioselective intramolecular esterification employing two sets of orthogonally removable side chain protecting groups for Ser/Thr and Asp. SAR study revealed that the ester linkage with Thr^3-Asp^9, the cis-conformation at Pro^7 and the N-terminal Phe^1-Ala^2 are the structural requirements for expression of the inhibitory activity. These findings were also supported by analyzing the solution and enzyme-bound structures of MST. Of particular note is that cis-Pro^7 may promote the internal hydrogen bond between the NH proton of Are and the carbonyl oxygen atom of the ester linkage with Thr^3-Asp^9 to protect its scissile bond of Met^4-Arg^5. This could be responsible for enhancing the potency. To elucidate the importance of backbone conformation at position 7, 16 and cis/trans-olefin analogs 17/18, in which cis/trans-olefins are substituted for the amide bond of Tyr^6-Ala^7, were synthesized. Although Ala^7 in 16 takes a trans-conformation in the solution structure, it takes a cis-conformation in the enzyme-bound structure. This implies that Ala^7 would isomerize from a trans to cis conformation when it binds to an enzyme, resulting in a certain inhibitory potency. However, the trans-olefin analog 18 lost the potency while the cis-olefin analog 17 displayed almost the same potency as that of MST. These results clearly indicated that the cis-conformation at position 7 is indispensable for binding to an enzyme in a canonical manner. By applying the structural motif of MST, we were able to rationally design protease inhibitory specificities that differed from those of the natural product.