Olech Zofia, Zaborska Wiesława, Kot Mirosława
Jagiellonian University, Faculty of Chemistry, 30-060 Kraków, Poland.
Food Chem. 2014 Feb 15;145:154-60. doi: 10.1016/j.foodchem.2013.08.044. Epub 2013 Aug 21.
The aim of this study was the elucidation of the inhibitory influence of Allium (garlic, onion, leek) and Brassica (cabbage, Brussels sprouts) plants juices, on jack bean urease activity. Concentrations of thiosulfinates, the compounds responsible for the inhibition, were determined in studied materials. The kinetics and mechanism of the inhibitions were investigated. Biphasic, time-dependent courses of the inhibition reactions were observed for all tested Allium and Brussels sprouts from Brassica. The cabbage material caused the monophasic course of the inhibition. In the presence of dithiothreitol, a total reactivation of the inhibited urease proceeded for the tested plants except for the onion. The onion juice modified urease, regained only half of the initial activity. The irreversible contribution was related to the presence of 1-propanethial-S-oxide, cepaenes and zwiebelanes formed in the onion juice. It was found that the thermal processing of the plant juices, results in the decrease of thiosulfinates concentration, as well as the efficiency of urease inhibition.
本研究的目的是阐明葱属植物（大蒜、洋葱、韭菜）和十字花科植物（卷心菜、抱子甘蓝）汁液对刀豆脲酶活性的抑制作用。测定了所研究材料中负责抑制作用的硫代亚磺酸盐的浓度。研究了抑制作用的动力学和机制。观察到所有测试的葱属植物和十字花科的抱子甘蓝的抑制反应均呈现双相、时间依赖性过程。卷心菜材料导致抑制反应呈单相过程。在二硫苏糖醇存在的情况下，除洋葱外，测试植物中被抑制的脲酶完全重新激活。洋葱汁使脲酶发生了修饰，仅恢复了初始活性的一半。不可逆作用与洋葱汁中形成的1-丙硫醛-S-氧化物、洋葱素和洋葱环素的存在有关。研究发现，植物汁液的热处理会导致硫代亚磺酸盐浓度降低以及脲酶抑制效率降低。
