The Study for the Solution Properties and the Thermal Dependence of Semi-flexible Polymers in a Wide Range of Concentration

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Cuticle collagen extracted from lugworm, Nereis Japonica, is a semi-flexible polymer with a molecular weight of about 1.6 x 10^6, a contour length of 18,000A, in 0,1M acetic acid, of which contour length was about six times as large as that of tropocollagen with a molecular weight of 30 x 10^4.The purpose of this research is to investigate the solution properties in a wide concentration range from dilute to semi-dilute and also the change of molecular shape during the thermal denaturation in more detail.The worthwhile results obtained from this research carried out from 1986 to 1988 are summarized as follows. 1) The concentration relating to the characteristic change of hydrodynamic properties for cuticle collagen almost coincide with those for tropocollagen and this value, 0.12g/dl, corresponds to the concentration, 0.16g/dl, obtained from the thermodynamic properties for both samples. It is also concluded that the change in hydrodynamic properties is not so drastic as compared with those in thermodynamic properties. 2) The thermal denaturation for both collagens is the transition from triple strand to single coil chain. The molecular shape change for cuticle collagen is not so sharp as compared with that for tropocollagen and also is step wise. 3) The concentration transitions for bothcollagen samples observed in this investigation indicate the possibility from semi-dilute range to concentrated range.