title: Endopeptidase character of monoclonal antibody i41-7 subunits.
abstract: We prepared six anti-idiotypic monoclonal antibodies (mAbs) against parent 41S-2 mAb whose light chain is a super catalytic antibody (41S-2-L) capable of degrading targeted HIV-1gp41 molecule. Out of the obtained six mAbs, i41-7 mAb showed the strongest affinity to the parent 41S-2 mAb. The three dimensional structure of i41-7 mAb was created by molecular modeling using the deduced amino acid sequence of the light and heavy chain of i41-7 mAb. It suggests that the light and heavy chain possess catalytic triad-like structure composed of Ser, His and Asp in their conformations. Both chains of i41-7 mAb could cleave peptide bond of some peptides such as a polypeptide, TP41-1 (TPRGPDRPEGIEEEGGERDRD), as anticipated. The cleaving reaction advanced in accordance with Michaelis-Menten equation. The catalytic efficiency (kcat/Km) of light and heavy chain was 9.1 x 10(3) and 1.7 x 10(4) M(-1) x min(-1), respectively, while the intact i41-7 mAb did not exhibit any catalytic activity. The first cleaved bond of the TP41-1 peptide by the light chain was between 14E and 15G in the sequence. It was revealed that both light and heavy chains had endopeptidase characteristics.
authors.affiliation: School of Biosciences, Hiroshima Prefectural University, Shobara City 727-0023, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Hatiuchi
authors.forename: Emi
authors.initials: E
authors.lastname: Hifumi
authors.forename: Yukie
authors.initials: Y
authors.lastname: Mitsuda
authors.forename: Taizo
authors.initials: T
authors.lastname: Uda
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D017151:Antibodies, Catalytic / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D000918:Antibody Specificity; D020134:Catalytic Domain / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D010450:Endopeptidases; D004797:Enzyme-Linked Immunosorbent Assay; D015700:HIV Envelope Protein gp41 / Q000378:metabolism*; D006825:Hybridomas; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry* / Q000302:isolation & purification; D007147:Immunoglobulin Light Chains / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D008958:Models, Molecular; D020836:Protein Structure, Quaternary
chemical_list: D000888:Antibodies, Anti-Idiotypic; D017151:Antibodies, Catalytic; D000911:Antibodies, Monoclonal; D015700:HIV Envelope Protein gp41; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D010450:Endopeptidases