Immunochemical Features of Complementarity Determining Region (CDR) Peptide in Anti Hemin Monoclonal Antibody

✍ Scribed by Emi Hifumi; Fumiko Morihara; Masanori Ishimaru; Keiko Morikawa; Kosuke Shimizu; Taizo Uda

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 130 KB
• Volume: 5
• Category: Article
• ISSN: 1075-2617
• DOI: 10.1002/(sici)1099-1387(199901)5:1<24::aid-psc169>3.0.co;2-l

✦ Synopsis

Messenger RNA purified from the anti hemin monoclonal antibody (1D3) secreting hybridoma was amplified by RT-PCR and the nueleotide and amino acid sequences of the antibody were determined. The role of complementarity determining regions (CDRs) in porphyrin recognition and its immunochemical feature of the antibody were investigated by using ELISA, fluorescence measurement and computational calculation of the conformation. All CDR peptides of the heavy chain of the antibody were synthesized and their affinity constants to porphyrins were determined. The value of CDR2 of heavy chain (CDRH2) of 1D3 was 1.5× 10 5 /M for protoporphyrin and 7×10 7 /M for TCPP, respectively, while that of the whole antibody showed to be 1.2 ×10 7 /M for TCPP. Though CDRH2 is a 17 meric peptide, it showed higher affinity than the whole antibody (1D3). Porphyrins can be considered to firmly bind with CDRH2, while CDRH3 is not involved in the antigen binding. CDR-1 may participate in the recognition with a small contribution. By the computational analysis of steric conformation, it was suggested that CDRH1 and CDRH2 co-operatively function in the recognition of porphyrin.