Abstract
Monoclonal antibodies directed against the enzymatically active A-fragment of diphtheria toxin were used to investigate further the structure-function relationships within fragment A. Of 16 such antibodies, all but two were directed against epitopes located within the carboxy-terminal 30–40 amino acids of fragment A. Interestingly, the antibodies recognize several epitopes in this small region and varied considerably in their effects on toxin functions. With regard to their effects on the enzymatic activity of fragment A, three types of antibodies were found: (1) antibodies which bind fragment A but fail to inhibit its ADP-ribosyltransferase activity, (2) antibodies which completely inhibit enzyme activity, and (3) antibodies which interact with fragment A to yield antigen-antibody complexes of diminished activity. The results are consistent with location of the catalytic center of fragment A within its carboxy-terminal ca 4000 dalton region.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
