Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China.
Wuhu Green Food Industry Research Institute Co., Ltd., Wuhu 241000, China.
J Agric Food Chem. 2024 Sep 25;72(38):21266-21275. doi: 10.1021/acs.jafc.4c06162. Epub 2024 Sep 13.
Urethanase is a promising biocatalyst for degrading carcinogen ethyl carbamate (EC) in fermented foods. However, their vulnerability to high ethanol and/or salt and acidic conditions severely limits their applications. In this study, a novel urethanase from (UH) was successfully discovered using a database search. UH shares 49.4% sequence identity with the reported amino acid sequences. It belongs to the Amidase Signature family and has a conserved "K-S-S" catalytic triad and the characteristic "GGSS" motif. The purified enzyme overexpressed in exhibits a high EC affinity (, 0.306 mM) and broad pH tolerance (pH 4.0-9.0), with an optimum pH 7.0. Enzyme activity remained at 58% in 12% (w/v) NaCl, and 80% in 10% (v/v) ethanol or after 1 h treatment with the same ethanol solution at 37 °C. UH has no hydrolytic activity toward urea. Under 30 °C, the purified enzyme (200 U/L) degraded about 15.4 and 43.1% of the EC in soy sauce samples (pH 5.0, 6.0), respectively, in 5 h. Furthermore, the enzyme also showed high activity toward the class 2A carcinogen acrylamide in foods. These attractive properties indicate their potential applications in the food industry.
尿烷酶是一种很有前途的生物催化剂，可用于降解发酵食品中的致癌物质乙基碳酸酯 (EC)。然而，它们对高乙醇和/或盐和酸性条件的脆弱性严重限制了它们的应用。在本研究中，通过数据库搜索成功发现了一种来自 (UH) 的新型尿烷酶。UH 与报道的氨基酸序列具有 49.4%的序列同一性。它属于酰胺酶特征家族，具有保守的“K-S-S”催化三联体和特征“GGSS”基序。在 中过表达的纯化酶表现出对 EC 的高亲和力 (, 0.306 mM) 和广泛的 pH 耐受性 (pH 4.0-9.0)，最佳 pH 为 7.0。在 12% (w/v) NaCl 中，酶活性保持在 58%，在 10% (v/v) 乙醇或在 37°C 下用相同的乙醇溶液处理 1 小时后，酶活性保持在 80%。UH 对尿素没有水解活性。在 30°C 下，纯化酶（200 U/L）在 5 小时内分别将酱油样品 (pH 5.0, 6.0) 中的 EC 降解了约 15.4%和 43.1%。此外，该酶对食品中的 2A 类致癌物丙烯酰胺也表现出高活性。这些有吸引力的特性表明它们在食品工业中有潜在的应用。
