菲律宾蛤仔闭壳肌组织学及其蛋白特性

为探讨菲律宾蛤仔Ruditapes philippinarum的加工特性与肌肉蛋白质特性的关系,对菲律宾蛤仔闭壳肌的组织形态、肌原纤维蛋白(Myofibrillar,Mf)的分布特性,以及与其低温凝胶化相关的特性等进行了分析。结果表明:闭壳肌肌纤维具有高度同向性,横纹肌呈直线柱状,平滑肌呈螺旋柱状;利用SDSPAGE电泳对两种类型肌肉的蛋白分布分析显示,横纹肌肌浆蛋白组分中存在相对分子质量为23 000的差异蛋白,且溶出更多的粗丝蛋白,平滑肌的Mf组分中存在标志性蛋白Myorod,且副肌球蛋白含量高,肌球和原肌球蛋白含量低,肌动蛋白含量接近;整个闭壳肌Mf的溶解性依赖于离子强度和有无三磷酸腺苷(Adenosine Triphosphate,ATP)的添加;Ca~(2+)-ATPase活性在中等离子强度(KCl浓度为0.30 mol/L)时最高,偏离中等离子强度后活性逐渐降低;参与交联的蛋白包括肌球蛋白、副肌球蛋白、原肌球蛋白,离子强度越高交联作用越显著。本研究结果可为探究经济贝类软体可食部位蛋白特性提供参考。

Characteristics of histology and protein in adductor of Manila clam Ruditapes philippinarum

In this study, the histomorphology, protein profile and myofibrillar ( Mf) gelation at low temperature were analyzed in muscle of Manila clam Ruditapes philippinarum for exploring the relationship between processing characteristics and properties of muscle protein. The results showed that adductor muscle fibers were highly homon-ymous in direction, as well as, striated and smooth muscle were linear and helical columnar, respectively. Analysis of protein distribution in two types of muscle by SDS-PAGE electrophoresis revealed that the sarcoplasmic protein was focused on 23000 presented in striated muscle, while the thick filament was dissolved. Compared with striated muscle, more level of myorod was only found in smooth muscle, in which there was higher content of paramyosin, and lower content of myosin and tropomyosin, an approximate content of actin. The solubility of Mf from whole ad-ductor was depended on ionic strength and ATP. The maximum value of Ca2+-ATPase activity was observed in the middle ionic strength ( KCl concentration 0 . 30 mol/L ) , and the activity was reduced gradually as the deviation from the middle ionic strength. Proteins involved in crosslinking process contained myosin, paramyosin and tropo-myosin, with the increase in ionic strength, the more significant effect of crosslinking. The findings provide a scien-tific reference for the further study on the protein properties of edible parts from economically important shellfish.