title: The thermal behavior of collagen in solution: effect of glycerol and 2-propanol.
abstract: The thermal stability of different solutions of collagen (Col), collagen mixed with glycerol (Col-G) and collagen mixed with 2-propanol (Col-P) was studied by differential scanning calorimetry (DSC), viscosity and fluorescence. The DSC and viscosity methods showed that glycerol increased the denaturation temperature of collagen about 2°C, while 2-propanol decreased it about 2°C. The values of intrinsic viscosity ([η]) for Col, Col-G and Col-P were 21.67, 20.20 and 24.71 dl/g, respectively. Huggins coefficient (k(H)) increased in the presence of glycerol and decreased in the presence of 2-propanol. It was suggested that glycerol promoted the dissolution of collagen molecular aggregates while 2-propanol enhanced the aggregation. Fluorescence spectra were investigated within the temperature ranging from 15 to 45°C. By comparing the sign of peaks in the two-dimensional (2D) fluorescence correlation maps, the orders of peak response were ∼360, ∼410>297 nm for Col and Col-G, and 297>∼360, ∼410 nm for Col-P, respectively. These indicated that the respondences of tyrosine residues, excimer-like species and bityrosine on the perturbation of temperature were different in the presence of glycerol and 2-propanol.
authors.affiliation: National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, PR China.
authors.forename: Jiheng
authors.initials: J
authors.lastname: Li
authors.forename: Guoying
authors.initials: G
authors.lastname: Li
mesh_terms: D019840:2-Propanol / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D003094:Collagen / Q000737:chemistry*; D005990:Glycerol / Q000737:chemistry*; D011489:Protein Denaturation; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014783:Viscosity
chemical_list: D012996:Solutions; D012997:Solvents; D003094:Collagen; D019840:2-Propanol; D005990:Glycerol