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(1) Carp ordinary muscle contained TGase activity of 1 .5unit per g of wet weight which was easily extractable with a solution at low ionic strength . The TGase, partially purified by DEAE-cellulose and gel filtration chromatographies , showed molecular weight of about 80,000 and Ca2+-requirement for full activation. These properties characterize the enzyme as a "tissue" TGase .(2) It was observed that rate and extent of TGase-catalyzed incorporation of MDC into myosin B and myofibrils were lower than those into acetylated casein .(3) The reactivity of TGase on carp myosin B and myofibrils was fluctuated by the conformational alteration of the substrate proteins; the extent of MDC incorporation appeared to be 2.4-fold elevated in "soluble myosin B" than "insoluble myosin B" or myofibrils at identical amount of the enzyme.(4) MDC was preferentially labeled on myosin heavy chain, actin, and troponin-T among the constituent proteins of myofibrils.

Dicyandiamide (DICY)-cured epoxy resins are important materials for structural adhesives and matrix resins for fiber reinforced prepregs. The objective of this study was to examine the mechanical and physical properties as well as the gel structures of the cured resins and discuss the relationships among them. Diglycidyl ether of bisphenol-A (DGEBA) oligomers were chosen as the common chemical structure of the epoxy resins. Four kinds of resin mixtures were formulated using the seven types of DGEBA oligomers having different molecular weight distributions. Three resin formulations having bimodal-type molecular weight distributions were designed to have almost identical rubbery plateau values of the storage modulus in dynamic mechanical analyses after curing, means that they had almost equivalent average crosslink density and basic chemical structure. However, the toughness, ductility, and environmental (heat and solvent) resistance of these three formulations were different. Atomic force microscopy revealed the existence of inhomogeneous nanoscale gel structures in these cured resins. The morphological differences in the gel structures in terms of their size, the connectivity, and the relative magnitude of the heterogeneity would cause the difference in several properties of the DICY-cured epoxy resins.

Wood-based epoxy resins were synthesized from resorcinol-liquefied wood. Wood was first liquefied in the presence of resorcinol with or without a sulfuric acid catalyst at high temperature. Because of the hydroxyl groups, the resorcinol-liquefied wood was considered as a precursor for synthesizing wood-based epoxy resin. Namely, the phenolic OH groups of the liquefied wood reacted with epichlorohydrin under alkali condition. By the glycidyl etherification, epoxy functionality was introduced to the liquefied wood. The epoxy functionality of the resins was controlled by the concentration of phenolic OH groups in the liquefied wood, which would be a dominant factor for crosslink density and properties of the cured epoxy resins. The flexural strength (150-180 MPa) and the modulus of elasticity (3.2 GPa) of the highly crosslinked wood-based epoxy resin were equivalent to those of the commercially available epoxy resin, diglycidyl ether of bisphenol A (DGEBA). Also, the shear adhesive strength of the wood-based epoxy resin was higher than that of DGEBA when plywood was used as the adhesive substrates. The mechanical and adhesive properties suggested that the wood-based epoxy resins would be well suited for matrix resins of natural plant-fiber reinforced composites.