Regulatory Support
A Drug Master File (DMF) for PeliCRM197® is maintained with the FDA to simplify your drug application. Upon request, a Letter of Authorization (LOA) may be provided for you to include reference to the PeliCRM197 DMF in your application. This will save you time and effort by not needing to describe PeliCRM197 as a starting material in your submission and enable FDA to reference the DMF in their review of your dossier. For submissions other than to US FDA, a Regulatory Support Package containing the technical information needed for inclusion in your drug application can be provided.
References
Please see below for a sample of references that discuss CRM197:
The amino-acid sequence of two non-toxic mutants of diphtheria toxin: CRM45 and CRM197.
Nucleic Acids Research | By G Giannini, R Rappuoli, and G Ratti | May 25, 1984
Abstract: The amino-acid sequences of two diphtheria toxin-related, non-toxic proteins, CRM45 and CRM197 , were deduced from the complete sequence of their genes: tox 45 and tox 197. CRM45 lacks the last 149 C-terminal amino-acid residues, but is otherwise identical to diphtheria toxin: a single C—-T transition introduces an “ochre” (TAA) termination signal in tox 45, after the codon for threonine-386. A single G—-A transition was also found in tox 197, leading to the substitution of glycine-52, present in the wild-type toxin, with glutamic acid in CRM197 . This aminoacid change is responsible for the loss of the NAD:EF2 ADP-ribosyltransferase activity in CRM197 , due most probably to an alteration of the NAD+ binding site.
Identification of diphtheria toxin receptor and a nonproteinous diphtheria toxin-binding molecule in Vero cell membrane
Journal of Cell Biology | By: Mekada, E., and Uchida, T. J. | August 1, 1988
Abstract: Two substances possessing the ability to bind to diphtheria toxin (DT) were found to be present in a membrane fraction from DT-sensitive Vero cells. One of these substances was found on the basis of its ability to bind DT and inhibit its cytotoxic effect. This inhibitory substance competitively inhibited the binding of DT to Vero cells. However this inhibitor could not bind to CRM197, the product of a missense mutation in the DT gene, and did not inhibit the binding of CRM197 to Vero cells. Moreover, similar levels of the inhibitory activity were observed in membrane fractions from DT-insensitive mouse cells, suggesting the inhibitor is not the DT receptor which is specifically present in DT-sensitive cells. The second DT-binding substance was found in the same Vero cell membrane preparation by assaying the binding of 125I-labeled CRM197. Such DT-binding activity could not be observed in membrane preparation from mouse L cells. From competition studies using labeled DT and CRM proteins, we conclude that this binding activity is due to the surface receptor for DT. Treatment of these substances with several enzymes revealed that the inhibitor was sensitive to certain RNases but resistant to proteases, whereas the DT receptor was resistant to RNase but sensitive to proteases. The receptor was solubilized and partially purified by chromatography on CM- Sepharose column. Immunoprecipitation and Western blotting analysis of the partially purified receptor revealed that a 14.5-kD protein is the DT receptor, or at least a component of it.
