| Summary: | University of Tokyo (東京大学) 博士(農学) The amino acid sequences of tropomyosins (TMs) have been determined for many species: Atlantic salmon Salmo salar (Heeley et al., 1995), bluefin tuna Tunnus tuna (Huang et al., 2004; Ochiai et al., 2010), kuruma prawn Marsupenaeus japonicas (Motoyama et al., 2007), mussel Mytilus edulis galloprovincialis (Iwasaki et al., 1997), rabbit Oryctolagus cuniculus (Stone and Smillie, 1978; Mak et al., 1979), tokobushi abalone Haliotis diversicolor (Chu et al., 2000), torafugu Takifugu rubripes (Ikeda et al., 2003), white croaker Pennahia argentata (Ochiai et al., 2001), walleye pollack Theragra chalcogramma (Ochiai et al., 2003), Yesso scallop Mizuhopecten yessoensis (Hasegawa, 2001), and zebrafish Danio rerio (Ohara et al., 1989). Invertebrate TMs are known as allergens and show higher viscosity than fish TMs, but the basic characteristics, in view of the comparative biochemistry, have not been studied so much. Elucidation of the relationship between amino acid sequence and stability would contribute to ascertain above interesting invertebrate TM properties. But the stability of invertebrate TM has been rarely measured (Inoue et al., 2004). The stability of TMs from fish (Huang and Ochiai, 2005) was estimated by differential scanning calorimetry (DSC) and it has been shown that fish TM, as rabbit TM (Potekhin and Privalov 1982), contains a few unfolding units. Thus, it would be adequate to measure the thermal stability of peptides or fragments. In Chapter 1, the stability of invertebrate TMs was investigated. TMs from the tail muscle of kuruma prawn, mantle muscle of Japanese common squid Todarodes pacificus, foot muscle of tokobushi abalone, and striated and smooth adductor muscles of Yesso scallop were purified and these stabilities were determined by circular dichroism (CD) spectrometry and DSC. The white croaker TM was used as control. In addition, three mRNAs encoding the smooth muscle TMs of the scallop have been sequenced (Hasegawa, 2001) and the major component was ...
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