Laboratory of Biochemistry and Enzymatic Engineering of Lipases, ENIS, BP 3038 Sfax, Tunisia.
Laboratory of Biochemistry and Enzymatic Engineering of Lipases, ENIS, BP 3038 Sfax, Tunisia; CNRS, Aix-Marseille Université, Enzymologie Interfaciale et Physiologie de la Lipolyse, Chemin Joseph Aiguier, France.
Int J Biol Macromol. 2017 Sep;102:1120-1129. doi: 10.1016/j.ijbiomac.2017.05.002. Epub 2017 May 3.
In order to identify fish enzymes displaying novel biochemical properties, we choose the common smooth-hound (Mustelus mustelus) as a starting biological material to characterize the digestive lipid hydrolyzing enzyme. A smooth-hound digestive lipase (SmDL) was purified from a delipidated pancreatic powder. The SmDL molecular weight was around 50kDa. Specific activities of 2200 and 500U/mg were measured at pH 9 and 40°C using tributyrin and olive oil emulsion as substrates, respectively. Unlike known mammal pancreatic lipases, the SmDL was stable at 50°C and it retained 90% of its initial activity after 15min of incubation at 60°C. Interestingly, bile salts act as an activator of the SmDL. It's worth to notice that the SmDL was also salt-tolerant since it was active in the presence of high salt concentrations reaching 0.8M. Fatty acid (FA) analysis of oil from the smooth-hound viscera showed a dominance of unsaturated ones (UFAs). Interestingly, the major n-3 fatty acids were DHA and EPA with contents of 18.07% and 6.14%, respectively. In vitro digestibility model showed that the smooth hound oil was efficiently hydrolyzed by pancreatic lipases, which suggests the higher assimilation of fish oils by consumers.
为了鉴定具有新型生化特性的鱼类酶，我们选择普通星鲨（Mustelus mustelus）作为起始生物材料来表征消化脂质水解酶。从脱脂的胰腺粉末中纯化出一种星鲨消化脂肪酶（SmDL）。SmDL 的分子量约为 50kDa。在 pH 9 和 40°C 下，使用三丁酸甘油酯和橄榄油乳液作为底物，分别测定了 2200 和 500U/mg 的比活性。与已知的哺乳动物胰腺脂肪酶不同，SmDL 在 50°C 下稳定，在 60°C 孵育 15min 后保留初始活性的 90%。有趣的是，胆汁盐作为 SmDL 的激活剂。值得注意的是，SmDL 也耐盐，因为它在高达 0.8M 的盐浓度下仍具有活性。星鲨内脏油的脂肪酸（FA）分析表明不饱和脂肪酸（UFAs）占主导地位。有趣的是，主要的 n-3 脂肪酸是 DHA 和 EPA，含量分别为 18.07%和 6.14%。体外消化模型表明，胰腺脂肪酶有效地水解了星鲨油，这表明消费者对鱼油的更高吸收。
