title: [Effect of specific antibodies on association of glyceraldehyde 3-phosphate dehydrogenase subunits].
abstract: The rabbit antibodies against glyceraldehyde 3-phosphate dehydrogenase (EC 1.2.1.12) from baker's yeast or rat muscle are strictly specific to the corresponding antigens and are not involved in the cross reaction. The interaction of specific antibodies with Fab-fragments does not affect the activity of the yeast enzyme which is in agreement with the previous data on the rat muscle enzyme. The antibodies against yeast dehydrogenase immobilized on BrCN-activated Sepharose were used for the preparation of the enzyme linked to the matrix by the antigen--antibody complex. The tetrameric enzyme molecule thus immobilized completely retains its activity and the ability to dissociate into dimers in the cold in the presence of ATP. The dimer which remains bound within the antigen--antibody complex retains its activity in the presence of agents causing inactivation and release of the second dimer into solution. The tetramer of yeast dehydrogenase covalently bound to the BrCN-activated Sepharose by one subunit is completely stable under conditions causing dissociation, when it exists in the complex with three molecules of specific antibodies. The binding of four molecules of Fab-fragments of specific antibodies per molecule of tetramer protects the rat muscle apoenzyme against anion-dependent cold inactivation and thermal inactivation in solution. The binding of two antibody molecules specific to rat muscle glyceraldehyde 3-phosphate dehydrogenase to the hybrid tetramer made up of yeast dehydrogenase dimer covalently linked to Sepharose and of rat muscle dehydrogenase dimer, prevents the dissociation of the tetramer (i.e. release of the "muscle" type dimer into solution). Gel filtration through Sepharose 6B of the apo-glyceraldehyde phosphate dehydrogenase complex with the Fab-fragments of specific antibodies demonstrated that the binding of the Fab-fragments shifts the tetramer in equilibrium or formed from dimers equilibrium in the apoenzyme solution towards the tetramer. It is concluded that the specific antibodies increase the intersubunit interactions in the oligomer by stabilizing the native tertiary structure of individual subunits.
mesh_terms: D000818:Animals; D000906:Antibodies; D000936:Antigen-Antibody Complex; D003429:Cross Reactions; D000939:Epitopes / Q000032:analysis*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000276:immunology / Q000378:metabolism*; D007140:Immunoglobulin Fab Fragments; D007700:Kinetics; D046911:Macromolecular Substances; D009132:Muscles / Q000201:enzymology; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000201:enzymology
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D000939:Epitopes; D007140:Immunoglobulin Fab Fragments; D046911:Macromolecular Substances; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases
vernacular_title: Vliianie spetsificheskikh antitel na assotsistsiiu sub"edinits glitseral'degid-3-fosfatdegidrogenazy.