Finiguerra M G, Iori R, Palmieri S
Istituto Sperimentale per le Colture Industriali, Italian Ministry of Agricultural and Forestry, Via di Corticella 133, I-40129 Bologna, Italy.
J Agric Food Chem. 2001 Feb;49(2):840-5. doi: 10.1021/jf000917h.
Crambe defatted meal contains 4-6% w/w of glucosinolates, with epiprogoitrin accounting for >90% of the total. This feature limits the use of the meal as feed due to the antinutritional properties of myrosinase-glucosinolate breakdown products. In this context, myrosinase activity assumes particular importance. In this study the total and soluble myrosinase activities have been evaluated directly on defatted meals of eight Crambe abyssinica varieties. The pH-stat method, which is the most suitable for assays in heterogeneous solid-water systems, was used. The total myrosinase activity in C. abyssinica varieties, determined using epiprogoitrin as substrate, ranged from 288 to 653 units g(-1). These activity values were up to 26 times higher than those obtained using other substrates, namely, sinigrin, glucosinalbin, glucotropaeolin, progoitrin, and glucoraphenin. Crambe myrosinase is unusual in that, unlike other Brassicaceae containing a typical main glucosinolate, it does not show the same specificity toward its natural substrates.
海甘蓝脱脂粕含有4%-6%（w/w）的硫代葡萄糖苷，其中表前甲状腺肿素占总量的90%以上。由于黑芥子酶-硫代葡萄糖苷分解产物的抗营养特性，这一特性限制了该粕作为饲料的使用。在这种情况下，黑芥子酶活性显得尤为重要。在本研究中，直接对8个海甘蓝品种的脱脂粕评估了总黑芥子酶活性和可溶性黑芥子酶活性。使用了最适合非均相固水体系分析的pH计法。以表前甲状腺肿素为底物测定的海甘蓝品种总黑芥子酶活性范围为288至653单位 g(-1)。这些活性值比使用其他底物（即黑芥子硫苷、葡糖芥苷、对羟基苯乙基硫代葡萄糖苷、前甲状腺肿素和葡糖莱菔素）获得的活性值高出26倍。海甘蓝黑芥子酶不同寻常之处在于，与含有典型主要硫代葡萄糖苷的其他十字花科植物不同，它对其天然底物不表现出相同的特异性。
