title: Microcalorimetric study of iodized and noniodized cells and C-phycocyanin of Spirulina platensis.
abstract: It was shown that eight stages of transition are observed in the heating process of Spirulina platensis cells in temperature range 5-140 degrees C. The first stage covers the temperature range 5-53 degrees C with maximum approximately 45 degrees C. The heat evolved in this temperature range is equal to 380 +/- 20 J/g of dry biomass, it does not change at scanning rate lower than 0.083 degrees C/min and belongs, mainly, to cell respiration in a stationary regime, in the dark. It was shown that endotherm approximately 66 degrees C belongs to denaturation of C-phycocyanin which denaturates in solutions with Td = 64.2 degrees C, deltaHd = 34.7 +/- 2.1 J/g and for it deltaHd(cal)/deltaH(V.H) is equal to 10.8 +/- 1.2. The endotherms with Td equal to 58 and 88 degrees C are connected with denaturation of phycobilisome proteins and endotherm with Td = 48 degrees C and deltaHd = 4.2J/g of dry biomass-with denaturation of protein which, apparently, is connected with cell respiration.
authors: Institute of Physics of the Georgian Academy of Sciences, Tbilisi 380077, Georgia.
authors: Levan S
authors: LS
authors: Topchishvili
authors: Shota I
authors: SI
authors: Barbakadze
authors: Anna I
authors: AI
authors: Khizanishvili
authors: George V
authors: GV
authors: Majagaladze
authors: Jamlet R
authors: JR
authors: Monaselidze
mesh_terms: D002151:Calorimetry; D002470:Cell Survival / Q000187:drug effects; D000458:Cyanobacteria / Q000737:chemistry / Q000166:cytology / Q000187:drug effects*; D008832:Microchemistry / Q000295:instrumentation; D045524:Phycobilisomes; D010798:Phycocyanin / Q000737:chemistry* / Q000302:isolation & purification; D011193:Potassium Iodide / Q000494:pharmacology*; D011489:Protein Denaturation; D020673:Protein Renaturation; D013696:Temperature; D013816:Thermodynamics
chemical_list: D045524:Phycobilisomes; D010798:Phycocyanin; D011193:Potassium Iodide