Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12 - 16, Belgrade, 11000, Republic of Serbia.
Amino Acids. 2019 May;51(5):829-838. doi: 10.1007/s00726-019-02724-3. Epub 2019 Mar 19.
Proteolytic enzymes are used for proteolysis and peptide synthesis which can be run in various conditions including low pH value and the presence of ethanol. The most common cysteine protease applied in acidic-alcoholic conditions is well-characterized papain. Ficin, which is closely related to papain in terms of proteolytic activity and substrate specificity, could potentially be applied in the alcoholic beverage industry and peptide synthesis. The aim of this study was to compare papain and ficin stability in process conditions. Comparative stability study showed that ficin as a mixture of different isoforms has a broader range of stability in respect of pH and cold storage stability, in comparison to papain. It retains about 70% of initial activity after 3-week cold storage at low pH and in the presence of ethanol. Unlike ficin, papain loses about 70% of initial activity in the same incubation period as it is more prone to non-native aggregation that was confirmed by FTIR analysis. The presence of multiple isoforms of ficin stabilizes the protease against cold denaturation and aggregation, making it more suitable for biotechnological and laboratory usage than single papain isoform. It is more cold-stable in alcoholic-acidic and acidic conditions suggesting possible replacement of papain with even lower enzyme concentration.
蛋白酶可用于蛋白水解和肽合成，可以在包括低 pH 值和乙醇存在的各种条件下进行。在酸性-乙醇条件下应用最广泛的半胱氨酸蛋白酶是木瓜蛋白酶。与木瓜蛋白酶在蛋白水解活性和底物特异性方面密切相关的无花果蛋白酶，可能在酒精饮料行业和肽合成中得到应用。本研究旨在比较木瓜蛋白酶和无花果蛋白酶在工艺条件下的稳定性。比较稳定性研究表明，无花果蛋白酶作为不同同工酶的混合物，在 pH 值和冷藏稳定性方面具有更宽的稳定性范围，与木瓜蛋白酶相比。在低 pH 值和乙醇存在下冷藏 3 周后，它仍保留约 70%的初始活性。与无花果蛋白酶不同，木瓜蛋白酶在相同的孵育期内失去约 70%的初始活性，因为它更容易发生非天然聚集，这一点通过傅里叶变换红外（FTIR）分析得到了证实。无花果蛋白酶的多种同工酶的存在稳定了蛋白酶，防止其在冷藏过程中变性和聚集，使其比单一木瓜蛋白酶同工酶更适合生物技术和实验室使用。它在酸性-乙醇和酸性条件下更耐冷，这表明可以用更低的酶浓度替代木瓜蛋白酶。
