title: The effect of non-enzymatic glycation on the unfolding of human serum albumin.
abstract: We monitored the unfolding of human serum albumin (HSA) and glycated human serum albumin (gHSA) subjected to guanidine hydrochloride (GndHCl) by using fluorescence and circular dichroism (CD) spectroscopy. A two-state model with sloping baselines best described the Trp-214 fluorescence unfolding measurements, while a three-state model best described the far-UV CD unfolding data. Glycation of HSA increased the [D](50%) point by approximately 0.20M. This corresponded to an increase in the free energy of unfolding of gHSA relative to HSA of 2.6kJ/mol. The intrinsic fluorescence of Trp-214 in gHSA is 0.72 of that of HSA and the far-UV CD spectrum of gHSA is nearly identical to that of HSA. These results showed that glycation altered the local structure around Trp-214 while not significantly impacting the secondary structure, and this alteration translated into an overall change in the stability of gHSA compared to HSA.
authors.affiliation: Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA 94132, USA.
authors.forename: Deanna L
authors.initials: DL
authors.lastname: Mendez
authors.forename: Russell A
authors.initials: RA
authors.lastname: Jensen
authors.forename: Laura A
authors.initials: LA
authors.lastname: McElroy
authors.forename: Jose M
authors.initials: JM
authors.lastname: Pena
authors.forename: Raymond M
authors.initials: RM
authors.lastname: Esquerra
mesh_terms: D002942:Circular Dichroism; D003198:Computer Simulation; D004798:Enzymes / Q000737:chemistry; D005947:Glucose / Q000737:chemistry*; D019791:Guanidine / Q000737:chemistry*; D006801:Humans; D008956:Models, Chemical; D008958:Models, Molecular; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D012709:Serum Albumin / Q000737:chemistry* / Q000648:ultrastructure*; D013050:Spectrometry, Fluorescence
chemical_list: D004798:Enzymes; D012709:Serum Albumin; D005947:Glucose; D019791:Guanidine