Biomaterial Database

Investigation of the symmetry of oligomeric enzymes with bifunctional reagents. 1975

F Hucho, and H Müllner, and H Sund

The symmetry of proteins composed of identical polypeptide chains has been investigated by means of cross-linking with bifunctional reagents and subsequent sodium dodecylsulfate-polyacrylamide gel electrophoresis. The majority of the investigations were performed with diimidates of different chain lengths (C3-C12), which react exclusively with amino groups. Aldolase, catalase, fumarase, pyruvate kinase, tetrameric proteins with identical polypeptide chains, reveal a D2 symmetry, i.e. they appear to be composed of two pairs of polypeptide chains. The validity of this conclusion is demonstrated with lactate dehydrogenase. This enzyme, shown by X-ray analysis to have a D2 symmetry, yields after cross-linking and subsequent polyacrylamide electrophoresis the band pattern expected for a protein with this quaternary structure and similar to the pattern obtained with the above enzymes. 2. The influence of the experimental conditions on the cross-linking reaction has been investigated. The selectivity of the bifunctional reagent for the different contact domains within the quaternary structure of a protein depends on the reaction time, the chain length and on the concentration of the reagent. In general the D2 symmetry becomes more obvious with increasing chain length and with increasing concentration of the diimidate. Diethylpyrocarbonate showed very little selectivity.

UI	MeSH Term	Description	Entries
D007094	Imides	Organic compounds containing two acyl groups bound to NITROGEN.	Imide
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D009842	Oligopeptides	Peptides composed of between two and twelve amino acids.	Oligopeptide
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D004047	Diethyl Pyrocarbonate	Preservative for wines, soft drinks, and fruit juices and a gentle esterifying agent.	Diethyl Dicarbonate,Diethyl Oxydiformate,Pyrocarbonic Acid Diethyl Ester,Diethylpyrocarbonate,Ethoxyformic Anhydride,Anhydride, Ethoxyformic,Dicarbonate, Diethyl,Oxydiformate, Diethyl,Pyrocarbonate, Diethyl
D004591	Electrophoresis, Polyacrylamide Gel	Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.	Polyacrylamide Gel Electrophoresis,SDS-PAGE,Sodium Dodecyl Sulfate-PAGE,Gel Electrophoresis, Polyacrylamide,SDS PAGE,Sodium Dodecyl Sulfate PAGE,Sodium Dodecyl Sulfate-PAGEs
D004798	Enzymes	Biological molecules that possess catalytic activity. They may occur naturally or be synthetically created. Enzymes are usually proteins, however CATALYTIC RNA and CATALYTIC DNA molecules have also been identified.	Biocatalyst,Enzyme,Biocatalysts
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining