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

1.谷氨酰胺转氨酶(TGase)是一种催化蛋白质中Ca~(2+)-(γ-谷氨酰基)赖氨酸形成共价键的酶。在11种海洋动物的肌肉组织中检测到该酶的活性范围为2.4-0.1单位/克。鲤鱼酶的催化性质和相对分子质量(80000 Da)与哺乳动物肝酶相似，但在Km值和钙离子依赖性等方面与从吸管肌肉中提纯的扇贝酶有显著不同。研究了鲤鱼TGase与不同鱼类肌动肌球蛋白的聚合反应速度，不同来源的肌动肌球蛋白有不同的反应活性，其中以大眼鳕鱼的肌动球蛋白活性最高，其次是虹鱼、鲑鱼、鳕鱼、白花鱼和鲤鱼。这些结果表明，TGase介导的肌动球蛋白的交联反应可能主要受Conform…的调控底物肌动球蛋白的影响因素随鱼种不同而不同。Suwari(定形)是一个非常重要的过程，对日本传统食品kamaboko的流变性有很大影响。众所周知，固化凝胶的形成取决于固化过程中产生的交联型肌球蛋白聚合物的量。在这份报告中，我们证明了交联型肌球蛋白聚合物是由鱼肉或鱼脯中的TGase酶作用产生的。研究了单价阳离子对肌球蛋白凝胶中TGase介导的交联的影响，结果表明，在0.2M以上加入氯化钠形成的凝胶和熟化的凝胶具有很强的坚固性，同时伴随着交联型肌球蛋白聚合物的形成。另一方面，含有KCl的鱼酱的凝固性与最终的煮熟凝胶强度无关。MH_4CL抑制凝胶体的形成。当鱼酱用水稀释时，酶的激活剂游离钙离子被发现是制备凝胶体的关键因素。鉴于凝固体是生产Kamaboko的传统制造工艺，涉及酶过程，我们的结果可能是重要的，并为进一步改进生产工艺和开发新的加工食品提供新的视角。较少

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