Polymerization Of Myosin Heavy Chain Research Articles

Role of SH<sub>a</sub> in the Polymerization of Myosin Heavy Chain during Ice Storage of Carp Actomyosin

Role of SH<sub>a</sub> in the Polymerization of Myosin Heavy Chain during Ice Storage of Carp Actomyosin

コイ・ミオシン加熱時のＳＳ結合によるタンパク質高分子化に及ぼす数種緩衝液の影響

Myosin from carp muscle was heated at 80°C in 0.6M NaCl solutions containing various kinds of buffer (pH 6.8), and the polymerization behavior of proteins through SS bonding (SS polymerization) was analyzed by SDS-polyacrylamide gel electrophoresis. In the phosphate buffer and Tris-HCl buffer, the oxidation of SH groups in myosin and SS polymerization of myosin heavy chain were promoted, which suggested that metal ions from the reagents used might be related to them. In Tris-maleate buffer and Tris-maleic anhydride buffer, the content of SH groups decreased more than in the phosphate buffer and in Tris-HCl buffer, but the decrease was not inhibited by a metal chelating reagent (EDTA) Moreover, in Tris-maleate buffer, SS polymerization was inhibited, and in Tris-maleic anhydride buffer, SS polymerization through covalent bonding other than SS bonding occurred. Therefore, it was concluded that these two buffers are not suitable for the research of SS polymerization.

Temperature and pH Affect Transglutaminase‐Catalyzed “Setting” of Crude Fish Actomyosin

ABSTRACTDynamic rheological properties of actomyosin from two species (Alaska pollock, Atlantic croaker) were monitored during preincubation (setting) at 25°C and 37°C. followed bv nronrammed (l°C/min) cookinn to 77°C. Added guinea pig liver transgluianase enhanced gelation, as indicated by increases in both storage modulus (G′) and percentage of polymerized myosin heavy chain (MHC). In the presence of added transglutaminase maximum G′ and MHC polymerization occurred at the same conditions of pH and temperature which were optimum for setting of surimi pastes. This suggested that the transglutaminase‐mediated setting reaction in surimi was constrained more by the conformation of the substrate (i.e., myosin) than by that of the enzyme.

Influence of Water Activity and Maillard Reaction on the Polymerization of Myosin Heavy Chain in Freeze-dried Squid Meat

Influence of Water Activity and Maillard Reaction on the Polymerization of Myosin Heavy Chain in Freeze-dried Squid Meat

Comparison of Reactivity of Transglutaminase to Various Fish Actomyosins.

It was found that all fish muscles analyzed contained transglutaminase (TGase) in an activity range of 2.41-0.10unit/g of wet weight. White croaker muscle has the highest activity, followed in descending order by carp, walleye pollack, chum salmon, atka mackerel, and rainbow trout.The reactivity of carp TGase to various fish actomyosins was investigated in terms of the velocity of polymerization of myosin heavy chain using a medium containing 5mg/ml actomyosin, 5mM CaCl2, 0.5M NaCl, and 0-0.05 unit carp TGase at pH 7.5 and 25°C. The rates of polymerization were significantly different according to the source of actomyosin, ranging from 13.5 to 0.1h-1•unit-1. The highest value was obtained from the actomyosin of walleye pollack, followed by those of rainbow trout, chum salmon, atka mackerel, white croaker, and carp. These results suggest that the TGase-mediated cross-linking reaction of myosin heavy chain may be mainly regulated by the conformational factor of the substrate actomyosin, depending on the species of fish.The combined effects of both factors, TGase content and reactivity, provided new insight into the species-specific set gel-formability of fish muscle pastes.

マイワシ肉とマサバ肉の坐り特性

Differences in the setting properties of sardine and Pacific mackerel were examined. The meat sol of sardine easily set after being kept at 20°C for only 20min; at the same time myosin heavy chain (MHC) polymers which were insoluble in SDS formed. But that of mackerel set hardly at all in the 30-40°C range, with no MHC polymerization. The setting phenomenon of sardine seemed to be caused by transglutaminase (TGase), as in the case of Alaska pollack, because significant inhibition of its activity was found due to the inhibitors of TGase, EDTA and methylamine. However, TGase activity was detected in the water soluble fraction of the muscle from seven species of fish including Pacific mackerel in the presence of 6mM CaCl2. When washed with 0.1N NaCl containing 2mM EDTA, minced sardine meat transformed its setting property to that of Pacific mackerel. On the other hand, Pacific mackerel meat changed its setting property to that of sardine after addition of 0.1% CaCl2.