作者:Miroslava ĎURANOVÁ、Ján HIRSCH、Katarína KOLENOVÁ、Peter BIELY
DOI:10.1271/bbb.90486
日期:2009.11.23
Glucuronoyl esterases are enzymes involved in microbial plant cell-wall degradation. In this study we purified and characterized two recombinant Phanerochaete chrysosporium glucuronoyl esterases, PcGE1 and PcGE2. The catalytic activity of these and previously described glucuronoyl esterases was investigated on new synthetic substrates, methyl esters of uronic acids and their glycosides, prepared by esterification with ethereal diazomethane.The data obtained indicate that the enzymes hydrolyzed efficiently not only esters of 4-O-methyl-d-glucuronic acid, but also methyl esters of d-glucuronic acid carrying a 4-nitrophenyl aglycon. Moreover, the fact that they did not recognize the 4-epimers of these compounds, the d-galacturonic acid derivatives, supports the hypothesis that these carbohydrate esterases attack ester linkages between 4-O-methyl-d-glucuronic acid of glucuronoxylan and lignin alcohols.
葡萄糖醛酸酯酶是一种参与微生物植物细胞壁降解的酶。在这项研究中,我们纯化并鉴定了两种重组的 Phanerochaete chrysosporium 葡萄醛酰酯酶 PcGE1 和 PcGE2。获得的数据表明,这些酶不仅能有效地水解 4-O-甲基-d-葡萄糖醛酸酯,还能有效地水解带有 4-硝基苯苷元的 d-葡萄糖醛酸甲酯。此外,它们不能识别这些化合物的 4-表聚体,即 d-半乳糖醛酸衍生物,这一事实支持了这样一种假设,即这些碳水化合物酯酶能攻击葡萄糖醛酸的 4-O-甲基-d-葡萄糖醛酸与木质素醇之间的酯连接。