Photon transmission study on conformational ordering of iota-carrageenan in CaCl2 solution.
Coil-to-double helix (c-h) and double helix-to-dimer (h-d) phase transitions of iota-carrageenan in CaCl(2) solution upon cooling were studied using photon transmission technique. Photon transmission intensity, I(tr) was monitored against temperature to determine the (c-h) and (h-d) transition temperatures (T(ch) and T(hd)) and activation energies (DeltaE(ch) and DeltaE(hd)). An extra dimer-to-dimer (d-d) transition was also observed during cooling at low temperature region. However, upon heating dimers disappear to double helices by making dimer-to-double helix (d-h) transition. Further heating resulted double helix-to-coil (h-c) transition at high temperature region. T(dh) and T(ch) temperatures and DeltaE(dh) and DeltaE(hc) activation energies were also determined. It was observed that T(hc) and T(ch) temperatures and DeltaE(dh) and DeltaE(hd) activation energies do not effected by carrageenan content. However, T(hd), T(dh) and T(dd) temperatures and DeltaE(ch) and DeltaE(hc) activation energies were found to be strongly correlated to the carrageenan content in the system.
Kara
Selim
S
Department of Physics, Trakya University, 22030 Edirne, Turkey.
Pekcan
Onder
O
D002122:Calcium Chloride / Q000494:pharmacology; D002236:Carbohydrate Conformation / Q000187:drug effects; D002351:Carrageenan / Q000737:chemistry*; D019281:Dimerization; D007700:Kinetics; D008956:Models, Chemical; D017785:Photons; D012996:Solutions; D013696:Temperature; D013816:Thermodynamics
D012996:Solutions; D002351:Carrageenan; D002122:Calcium Chloride