Kang Hye-Jin, Tagami Takayoshi, Okuyama Masayuki
1 Research Faculty of Agriculture, Hokkaido University.
J Appl Glycosci (1999). 2024 Aug 20;71(3):91-94. doi: 10.5458/jag.jag.JAG-2024_0004. eCollection 2024.
We recently found two α-L-glucosidases, which can hydrolyze -nitrophenyl α-L-glucopyranoside (PNP L-Glc) rather than -nitrophenyl α-L-fucopyranoside, in glycoside hydrolase family 29. This study evaluated their substrate specificity for -nitrophenyl α-L-rhamnopyranoside (PNP L-Rha), α-L-quinovopyranoside (PNP L-Qui), and α-L-xylopyranoside (PNP L-Xyl), of which structure is similar to PNP L-Glc. The two α-L-glucosidases had little activity toward PNP L-Rha. They exhibited higher / values for PNP L-Qui but smaller for PNP L-Xyl than for PNP L-Glc. The molecular docking studies indicated that these specificities were correlated well with the active-site structure of the α-L-glucosidases. The finding that α-L-quinovoside, which has been suggested to occur in nature, is also a substrate for α-L-glucosidases indicates that this enzyme are not solely dedicated to α-L-glucoside hydrolysis.
我们最近在糖苷水解酶家族29中发现了两种α-L-葡萄糖苷酶，它们能够水解对硝基苯基α-L-吡喃葡萄糖苷（PNP L-Glc），而不是对硝基苯基α-L-吡喃岩藻糖苷。本研究评估了它们对结构与PNP L-Glc相似的对硝基苯基α-L-吡喃鼠李糖苷（PNP L-Rha）、α-L-奎诺吡喃糖苷（PNP L-Qui）和α-L-吡喃木糖苷（PNP L-Xyl）的底物特异性。这两种α-L-葡萄糖苷酶对PNP L-Rha几乎没有活性。它们对PNP L-Qui的催化效率/值较高，但对PNP L-Xyl的催化效率/值比对PNP L-Glc的小。分子对接研究表明，这些特异性与α-L-葡萄糖苷酶的活性位点结构密切相关。有研究表明自然界中存在α-L-奎诺糖苷，它也是α-L-葡萄糖苷酶的底物，这一发现表明该酶并非仅专一作用于α-L-糖苷水解。
