Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea.
Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea.
Molecules. 2021 Mar 28;26(7):1901. doi: 10.3390/molecules26071901.
We investigated the effect of endogenous cathepsin L on surimi gel produced from olive flounder (). The amino acid sequences of six proteins predicted or identified as cathepsin L were obtained from the olive flounder genome database, and a phylogenetic analysis was conducted. Next, cathepsin L activity toward -α-benzyloxycarbonyl-l-phenylalanyl-l-arginine-(7-amino-4-methylcoumarin) (Z-F-R-AMC) was detected in crude olive flounder extract and a crude enzyme preparation. A considerable decrease in the level of myosin heavy chain (MHC) in surimi occurred during autolysis at 60 °C. In contrast, the levels of actin, troponin-T, and tropomyosin decreased only slightly. To prevent protein degradation by cathepsin L, a protease inhibitor was added to surimi. In the presence of 1.0% protease inhibitor, the autolysis of olive flounder surimi at 60 °C was inhibited by 12.2%; the degree of inhibition increased to 44.2% as the inhibitor concentration increased to 3.0%. In addition, the deformation and hardness of modori gel increased as the inhibitor concentration increased to 2.0%. Therefore, cathepsin L plays an important role in protein degradation in surimi, and the quality of surimi gel could be enhanced by inhibiting its activity.
我们研究了内源性组织蛋白酶 L 对来自橄榄石斑鱼（）鱼糜凝胶的影响。从橄榄石斑鱼基因组数据库中获得了 6 种预测或鉴定为组织蛋白酶 L 的蛋白质的氨基酸序列，并进行了系统发育分析。接下来，在粗制橄榄石斑鱼提取物和粗制酶制剂中检测了组织蛋白酶 L 对 -α-苯甲氧基羰基-l-苯丙氨酰-l-精氨酸-（7-氨基-4-甲基香豆素）（Z-F-R-AMC）的活性。在 60°C 自溶过程中，鱼糜中的肌球蛋白重链（MHC）水平显著下降。相比之下，肌动蛋白、肌钙蛋白 T 和原肌球蛋白的水平仅略有下降。为了防止组织蛋白酶 L 引起的蛋白质降解，在鱼糜中添加了蛋白酶抑制剂。在 1.0%蛋白酶抑制剂存在的情况下，12.2%抑制了 60°C 下橄榄石斑鱼鱼糜的自溶；随着抑制剂浓度增加到 3.0%，抑制率增加到 44.2%。此外，随着抑制剂浓度增加到 2.0%，调制凝胶的变形和硬度增加。因此，组织蛋白酶 L 在鱼糜中的蛋白质降解中起重要作用，通过抑制其活性可以提高鱼糜凝胶的质量。
