Biomaterial Database

Fc intermediate (Fci), a papain-generated fragment of human IgG, intermediate in charge, molecular weight and cleavage between the Fc and Fc' fragments of IgG. 1985

F A Nardella, and D C Teller

Fc intermediate (Fci) is a papain-generated fragment of human IgG which is intermediate in charge, mol. wt and state of cleavage between the Fc and Fc' fragments of IgG. It is composed of two polypeptide chains of unequal mol. wt held together by non-covalent bonds between the C gamma 3 regions. The larger polypeptide chain has both a C gamma 2 and C gamma 3 domain and its N-terminus is at Leu 235 (60%) and Leu 234 (40%) (IgGl Eu numbering). The smaller polypeptide chain is composed of a C gamma 3 domain with its N-terminus at Gly 341. The carboxy-termini obtained by carboxypeptidase digestion and by a computer program which determined the most probable sequences by fitting the amino acid compositions to the sequence of IgG Eu Fc were heterogeneous involving residues 440-446 for the large polypeptide chain and 429-436 for the small one. The calculated mol. wt of the large polypeptide chain was 26,183, assuming the N-terminus at Leu 234 and C-terminus at 446 and including the carbohydrate moiety. The calculated mol. wt for the small polypeptide chain was 10,682, with the N-terminus at 341 and assuming the C-terminus at 434, for a combined mol. wt of 36,865 for the Fci fragment. Sedimentation equilibrium ultracentrifugation of Fci under non-dissociating conditions showed an Mn of 36,200 +/- 1200, an Mw of 36,400 +/- 600 and an Mz of 37,000 +/- 300 g/mole. The best yields of Fc were obtained with a 6-hr digestion and the best yields of Fcl and Fc' were obtained with digestion for 18 hr in phosphate buffer. Digestion in Tris buffer for 18 hr gave results similar to the 18-hr digestion in phosphate buffer except the yields of Fc' were less. This fragment may be useful for exploring biological functions of human IgG Fc. In addition, some Fc fragments obtained by papain digestion of human IgG either in phosphate or Tris buffer are not covalently bonded and are probably cleaved on the carboxy-terminal side of the interchain disulfide bonds at Leu 234 or Leu 235, the N-termini for the large polypeptide chain of Fci. This indicates that, if disulfide bonded Fc fragments are needed, gel filtration under dissociating conditions will be necessary to remove non-covalently bonded Fc.

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
D007122	Immunoelectrophoresis	A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.
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
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
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D010206	Papain	A proteolytic enzyme obtained from Carica papaya. It is also the name used for a purified mixture of papain and CHYMOPAPAIN that is used as a topical enzymatic debriding agent. EC 3.4.22.2.	Tromasin
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D002852	Chromatography, Ion Exchange	Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.	Chromatography, Ion-Exchange,Ion-Exchange Chromatography,Chromatographies, Ion Exchange,Chromatographies, Ion-Exchange,Ion Exchange Chromatographies,Ion Exchange Chromatography,Ion-Exchange Chromatographies
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
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man