Studies on enzymatic properties of transglutaminase from the muscles of aquatic animals with applications to surimi-based products

1. 谷氨酰胺转酶（TGase）是一种在蛋白质中催化Ca^<2+>-依赖性共价epsilon -（γ -谷氨酰基）赖氨酸交联形成的酶。在所分析的11种海洋动物的所有肌肉组织中均鉴定出该酶，其活性范围为2.4-0.1单位/g。鲤鱼酶的催化性能和分子量（80000 Da）与已知的哺乳动物肝酶相似，但在km值和Ca^<2+>依赖性等酶特性上与从内收肌中纯化的扇贝酶有显著不同。研究了鲤鱼TGase对各种鱼类肌动凝蛋白的反应性，考察了不同来源的肌动凝蛋白的聚合速度；平眼明太鱼肌动球蛋白含量最高，虹鳟鱼次之，大马哈鱼次之，鲐鱼次之，青花鱼次之，鲤鱼次之。这些结果表明，tgase介导的肌动球蛋白交联反应可能主要受底物肌动球蛋白的多种民族因子的调控。Suwari（设定）是一个非常重要的过程，对日本传统食品kamaboko的流变特性有重要影响。众所周知，凝固凝胶的形成取决于在凝固过程中产生的交联肌球蛋白聚合物的数量。在本报告中，我们证明了交联肌球蛋白聚合物是由鱼肌肉或鱼糜中含有的TGase酶促产生的。通过研究一价阳离子对tgase介导的肌凝蛋白交联的影响，发现在0.2M以上的NaCl溶液中，形成了牢固的凝固和熟化凝胶，同时形成了交联的肌凝蛋白聚合物。另一方面，含有KCl的鱼膏的凝固与最终熟凝胶强度无关。MH_4Cl抑制凝固凝胶的形成。当鱼膏用水稀释时，发现游离钙离子是酶的活化剂，是制备凝固凝胶的关键因素。我们的研究结果可能具有重要意义，因为传统的卡马博科生产工艺涉及酶促过程，并为进一步改进生产工艺和开发新的加工食品提供了新的见解。少

1. Transglutaminase (TGase) is an enzyme that catalyzes Ca^<2+>-dependently the formation of covalent epsilon -(gamma -glutamyl)lysine cross-links in proteins. The enzyme was identified in all muscle tissues of eleven marine animals analyzed and contained in the activity range of 2.4-0.1 unit/g. Carp enzyme is similar in catalytic properties and molecular weight (80,000 Da) to well known mammalian liver enzymes, but significantly differs from scallop enzyme, which was purified from the aductor muscle, in enzymatic properties such as km value and Ca^<2+> dependency. Reactivity of carp TGase to various fish actomyosins was investigated in terms of the velocity of polymerization of actomyosin and was different in source of actomyosin; the highest values was obtained from walleye pollack actomyosin, followed by rainbow trout, chum salmon, atka mackerel, white croaker, and carp. These results suggest that TGase-mediated cross-linking reaction of actomyosin may be mainly regulated by conform … More ational factors of the substrate actomyosin depending upon fish species.2. Suwari (setting) is a very important process with significant influence on the rheological properties of kamaboko, a traditional food in Japan. It is well known that set gel is formed depending on the amount of cross-linked myosin polymers produced during the setting. In this report we demonstrated that the cross-linked myosin polymers are enzymatically produced by TGase contained in fish muscle or surimi. The studies on effects of monovalent cations on TGase-mediated cross-linking of myosin in a set gel revealed that the set and cooked gels having strong firmness were formed by the addition of NaCl to above 0.2M with concomitant formation of cross-linked myosin polymers. On the other hand the setting of the fish paste containing KCl was not linked to the final cooked gel strength. MH_4Cl inhibited the formation of set gel. Free calcium ion, an activator of the enzyme, was found to be a critical factor to prepare the set gel when fish paste was diluted with water.Our results may be important in view of the fact that setting, a traditional manufacturing process for production of kamaboko, involves enzymatic process, and provide new insight into further improvement of the manufacturing process and developing new fabricated foods. Less