Biomaterial Database

Dissociation and denaturation equilibria and kinetics of a homogeneous human immunoglobulin Fab fragment. 1976

E S Rowe

The conformational equilibria and the kinetics of the approach to equilibrium of an IgG1 myeloma (Wes) Fab fragment (SSFab) and its mildly reduced and S-carboxyamidomethylated derivative (RAFab) were studied as a function of guanidine hydrochloride concentration. The unimolecular denaturation of SSFab, the bimolecular denaturation of RAFab, and the denaturation of Wes L chain reported previously (Rowe, E. S., and Tanford, C., (1973), Biochemistry 12, 4822) are interpreted in terms of the domain structure and evaluated in terms of the thermodynamic stability of the protein and the covalent and noncovalent interactions among its subunits. The Fd-L interactions are found to be extremely strong and are maintained at concentrations of denaturant sufficient to denature the individual domains. It is shown that all of the data are consistent with a two region structure for Fab, one composed of the vL and vH domains, and the other composed of the cL and cH domains, so that there are two sites of noncovalent Fd-L interactions. One region, identified as the C region, is found to be 10(2)-10(4) times more stable than the other; this difference in stability is attributed largely to a stronger and more extensive interaction between the domains of this region. The kinetics of the approach to equilibrium are found to be extremely slow in the center of the transitions, requiring up to a week for equilibration for RAFab, and several months for SSFab. This unusual kinetic behavior is shown to be due to the strong Fd-L interaction under conditions where the monomeric domains are unstable.

UI	MeSH Term	Description	Entries
D007074	Immunoglobulin G	The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.	Gamma Globulin, 7S,IgG,IgG Antibody,Allerglobuline,IgG(T),IgG1,IgG2,IgG2A,IgG2B,IgG3,IgG4,Immunoglobulin GT,Polyglobin,7S Gamma Globulin,Antibody, IgG,GT, Immunoglobulin
D007128	Immunoglobulin Fragments	Partial immunoglobulin molecules resulting from selective cleavage by proteolytic enzymes or generated through PROTEIN ENGINEERING techniques.	Antibody Fragment,Antibody Fragments,Ig Fragment,Ig Fragments,Immunoglobulin Fragment,Fragment, Antibody,Fragment, Ig,Fragment, Immunoglobulin,Fragments, Antibody,Fragments, Ig,Fragments, Immunoglobulin
D007140	Immunoglobulin Fab Fragments	Univalent antigen-binding fragments composed of one entire IMMUNOGLOBULIN LIGHT CHAIN and the amino terminal end of one of the IMMUNOGLOBULIN HEAVY CHAINS from the hinge region, linked to each other by disulfide bonds. Fab contains the IMMUNOGLOBULIN VARIABLE REGIONS, which are part of the antigen-binding site, and the first IMMUNOGLOBULIN CONSTANT REGIONS. This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme PAPAIN.	Fab Fragment,Fab Fragments,Ig Fab Fragments,Immunoglobulins, Fab Fragment,Fab Immunoglobulin Fragments,Immunoglobulin Fab Fragment,Immunoglobulins, Fab,Fab Fragment Immunoglobulins,Fab Fragment, Immunoglobulin,Fab Fragments, Immunoglobulin,Fragment Immunoglobulins, Fab,Fragment, Fab,Immunoglobulin Fragments, Fab
D007141	Immunoglobulin Fc Fragments	Crystallizable fragments composed of the carboxy-terminal halves of both IMMUNOGLOBULIN HEAVY CHAINS linked to each other by disulfide bonds. Fc fragments contain the carboxy-terminal parts of the heavy chain constant regions that are responsible for the effector functions of an immunoglobulin (COMPLEMENT fixation, binding to the cell membrane via FC RECEPTORS, and placental transport). This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme PAPAIN.	Fc Fragment,Fc Fragments,Fc Immunoglobulin,Fc Immunoglobulins,Ig Fc Fragments,Immunoglobulin Fc Fragment,Immunoglobulins, Fc,Immunoglobulins, Fc Fragment,Fc Fragment Immunoglobulins,Fc Fragment, Immunoglobulin,Fc Fragments, Ig,Fc Fragments, Immunoglobulin,Fragment Immunoglobulins, Fc,Fragment, Fc,Fragments, Ig Fc,Immunoglobulin, Fc
D007147	Immunoglobulin Light Chains	Polypeptide chains, consisting of 211 to 217 amino acid residues and having a molecular weight of approximately 22 kDa. There are two major types of light chains, kappa and lambda. Two Ig light chains and two Ig heavy chains (IMMUNOGLOBULIN HEAVY CHAINS) make one immunoglobulin molecule.	Ig Light Chains,Immunoglobulins, Light-Chain,Immunoglobulin Light Chain,Immunoglobulin Light-Chain,Light-Chain Immunoglobulins,Chains, Ig Light,Chains, Immunoglobulin Light,Immunoglobulins, Light Chain,Light Chain Immunoglobulins,Light Chain, Immunoglobulin,Light Chains, Ig,Light Chains, Immunoglobulin,Light-Chain, Immunoglobulin
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009194	Myeloma Proteins	Abnormal immunoglobulins characteristic of MULTIPLE MYELOMA.	M Components,Proteins, Myeloma
D009905	Optical Rotatory Dispersion	The method of measuring the dispersion of an optically active molecule to determine the relative magnitude of right- or left-handed components and sometimes structural features of the molecule.	Dispersion, Optical Rotatory,Rotatory Dispersion, Optical
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
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