College of Animal Science and Technology, Northwest A & F University, Yangling, China.
Fish Physiol Biochem. 2012 Jun;38(3):603-13. doi: 10.1007/s10695-011-9541-9. Epub 2011 Sep 6.
A series of biochemical determination and electrophoretic observations have been conducted to analyze the activities and characteristics of protease, α-amylase, and lipase of paddlefish Polyodon spathula. The results obtained have been compared with those of bighead carp (Aristichthys nobilis) and hybrid sturgeon (Huso dauricus ♀ × Acipenser schrenki Brandt ♂), in order to increase available knowledge of the physiological characteristics of this sturgeon species and to gain information with regard to its nutrition. Further, a comparative study of enzymatic activity, distribution, and characterization between commercial feed-reared paddlefish (CG) and natural live food-reared (NG) paddlefish was conducted. Results showed that higher proteolytic activity was observed in the pH range 2.5-3.0 and at a pH of 7.0 for paddlefish. Levels of acid protease activity of paddlefish were similar to that of hybrid sturgeon, and significantly higher than that of bighead carp. The inhibition assay of paddlefish showed that the rate of inhibition of tosyl-phenylalanine chloromethyl ketone was approximately 2.6-fold that of tosyl-lysine chloromethyl ketone. There was no significant difference observed for acid protease activity between PG and CG groups, whereas the activity of alkaline protease, α-amylase, and lipase in the PG group were significantly lower than those in the CG group. The substrate sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis further showed that there were certain types of enzymes, especially α-amylase, with similar molecular mass in the paddlefish and hybrid sturgeon. It can be inferred that acid digestion was main mechanism for protein hydrolysis in paddlefish, as reported for other fishes with a stomach. This indicates that the paddlefish requires higher alkaline protease, α-amylase, and lipase activity to digest natural live food.
已经进行了一系列生化测定和电泳观察，以分析白鲟 Polyodon spathula 的蛋白酶、α-淀粉酶和脂肪酶的活性和特性。将所得结果与鳙鱼（Aristichthys nobilis）和杂交鲟（Huso dauricus♀×Acipenser schrenki Brandt♂）进行比较，以便增加对该鲟鱼物种生理特性的了解，并获得有关其营养的信息。此外，还对商业饲料养殖的白鲟（CG）和天然活饵养殖的白鲟（NG）的酶活性、分布和特性进行了比较研究。结果表明，白鲟在 pH 值为 2.5-3.0 和 7.0 时表现出较高的蛋白水解活性。白鲟的酸性蛋白酶活性水平与杂交鲟相似，明显高于鳙鱼。白鲟的抑制试验表明，甲苯酰苯丙氨酸氯甲基酮的抑制率约为甲苯酰赖氨酸氯甲基酮的 2.6 倍。PG 和 CG 组之间的酸性蛋白酶活性没有显著差异，而 PG 组的碱性蛋白酶、α-淀粉酶和脂肪酶活性明显低于 CG 组。底物十二烷基硫酸钠聚丙烯酰胺凝胶电泳分析进一步表明，白鲟和杂交鲟存在某些类型的酶，特别是α-淀粉酶，具有相似的分子量。可以推断，正如其他有胃的鱼类所报道的那样，酸性消化是白鲟蛋白水解的主要机制。这表明白鲟需要更高的碱性蛋白酶、α-淀粉酶和脂肪酶活性来消化天然活饵。
