Assessing the activity of acid pepsin‐like protease is a common procedure in many biological, physiological and nutritional studies in gastric fish species. After reviewing the available literature on fish digestive acid proteases (stomach acid pepsin‐like proteases), especially those species of relevance for aquaculture purposes, published during a time span of ten years (2008–2018), authors detected some possible methodological and/or interpretative inconsistencies in this kind of studies when quantifying pepsin‐like enzymes. Thus, we concluded that special attention should be paid on the following issues when assessing digestive acid protease activity: (i) the proper preparation of stomach extracts, (ii) the use of the proper reaction conditions at the normal range of physiological pH and temperature values, and (iii) the proper quantification of the number of peptide bonds hydrolyzed for acid protease unit calculation. The implementation of these recommendations, and the proposal of more suitable (previously tested) methodological steps, will promote the standardization of acid pepsin‐like protease analytical procedures, as well as improve the reliability of comparative studies dealing with this proteolytic enzyme between different fish species of aquacultural importance.

中文翻译：

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胃蛋白酶样酸蛋白酶定量在水产养殖研究中的重要性：对可用程序进行修订并提出新的评估方案

在胃鱼类的许多生物学，生理学和营养学研究中，评估酸性胃蛋白酶样蛋白酶的活性是一种常见程序。在回顾了有关鱼类消化酸性蛋白酶（胃酸胃蛋白酶样蛋白酶）的现有文献，尤其是在十年（2008-2018年）内发表的与水产养殖相关的物种后，作者发现了一些可能的方法论和/或在定量分析胃蛋白酶样酶时，此类研究存在解释不一致的情况。因此，我们得出结论，在评估消化酸蛋白酶活性时，应特别注意以下问题：（i）胃提取物的正确制备，（ii）在生理pH和温度的正常范围内使用适当的反应条件价值观 （iii）适当定量水解的肽键的数目，以计算酸性蛋白酶单位。这些建议的实施以及更合适（先前经过测试）的方法步骤的建议，将促进酸性胃蛋白酶样蛋白酶分析程序的标准化，并提高不同鱼类之间处理这种蛋白水解酶的比较研究的可靠性。对水产养殖的重要性