Department of Food Science and Technology, National University of Singapore, 2 Science Drive 2, Singapore 117542, Singapore.
Department of Food Science and Technology, National University of Singapore, 2 Science Drive 2, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Jiangsu 215123, China.
Food Chem. 2023 Mar 15;404(Pt A):134438. doi: 10.1016/j.foodchem.2022.134438. Epub 2022 Sep 28.
Organosulfides are responsible for the characteristic aroma of Parkia speciosa Hassk seeds (stink bean) yet its formation mechanism from the precursor djenkolic acid has not been characterized. Herein, the aqueous extracts of stink bean were analysed by LC/MS, and the volatile components were extracted and analysed by GC/QTOF/MS. Using enzyme purification methods, we isolated and characterized C-S lyase from ripe stink beans. The active C-S lyase is composed of two protein subunits with molecular weights of 58 kDa and 45 kDa and forms agglomerates in solution with an average particle size of ∼ 50 nm. The enzyme was stable at pH 7.0-11.0 with an optimal pH ∼ 9.0 and was more stable at 25-40 °C with an optimal activity at 50 °C. It shows high substrate specificity towards l-cystine and l-djenkolic acid by forming methanedithiol, which leads to the formation of 1,2,4-trithiolane. C-S lyase is a promising biocatalyst for natural flavour production.
有机硫化物是 Parkia speciosa Hassk 种子（臭豆）特征香气的原因，但从前体 djenkolic 酸形成的机制尚未得到表征。在此，通过 LC/MS 分析臭豆的水提取物，通过 GC/QTOF/MS 提取和分析挥发性成分。使用酶纯化方法，我们从成熟的臭豆中分离并表征了 C-S 裂合酶。活性 C-S 裂合酶由两个分子量为 58 kDa 和 45 kDa 的蛋白质亚基组成，在溶液中形成聚集体，平均粒径约为 50nm。该酶在 pH 7.0-11.0 之间稳定，最佳 pH 约为 9.0，在 25-40°C 之间更稳定，最佳活性在 50°C。它对 l-胱氨酸和 l-djenkolic 酸表现出高的底物特异性，通过形成甲硫二硫醇，导致 1,2,4-三硫杂环戊烷的形成。C-S 裂合酶是一种有前途的天然风味生产用生物催化剂。
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