title: Mechanism of thermal aggregation of rabbit muscle glyceraldehyde-3-phosphate dehydrogenase.
abstract: Thermal denaturation and aggregation of rabbit muscle glyceraldehyde-3-phosphate dehydrogenase (GAPDH) have been studied using differential scanning calorimetry (DSC), dynamic light scattering (DLS), and analytical ultracentrifugation. The maximum of the protein thermal transition (T(m)) increased with increasing the protein concentration, suggesting that the denaturation process involves the stage of reversible dissociation of the enzyme tetramer into the oligomeric forms of lesser size. The dissociation of the enzyme tetramer was shown by sedimentation velocity at 45 degrees C. The DLS data support the mechanism of protein aggregation that involves a stage of the formation of the start aggregates followed by their sticking together. The hydrodynamic radius of the start aggregates remained constant in the temperature interval from 37 to 55 degrees C and was independent of the protein concentration (R(h,0) approximately 21 nm; 10 mM sodium phosphate, pH 7.5). A strict correlation between thermal aggregation of GAPDH registered by the increase in the light scattering intensity and protein denaturation characterized by DSC has been proved.
authors.affiliation: Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky 33, Moscow 119071, Russia. markossian@inbi.ras.ru
authors.forename: Kira A
authors.initials: KA
authors.lastname: Markossian
authors.forename: Helen A
authors.initials: HA
authors.lastname: Khanova
authors.forename: Sergey Yu
authors.initials: SY
authors.lastname: Kleimenov
authors.forename: Dmitrii I
authors.initials: DI
authors.lastname: Levitsky
authors.forename: Natalia A
authors.initials: NA
authors.lastname: Chebotareva
authors.forename: Regina A
authors.initials: RA
authors.lastname: Asryants
authors.forename: Vladimir I
authors.initials: VI
authors.lastname: Muronetz
authors.forename: Luciano
authors.initials: L
authors.lastname: Saso
authors.forename: Igor K
authors.initials: IK
authors.lastname: Yudin
authors.forename: Boris I
authors.initials: BI
authors.lastname: Kurganov
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006358:Hot Temperature; D007700:Kinetics; D009132:Muscles / Q000201:enzymology*; D011817:Rabbits; D014461:Ultracentrifugation
chemical_list: D005987:Glyceraldehyde-3-Phosphate Dehydrogenases