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G Grassy

Publications and source records attributed to G Grassy.

21 records · Page 2Linked to original sources
PubMed1988

The biooxidation of cytotoxic ellipticine derivatives: a key to structure-activity relationship studies?

In the family of ellipticine derivatives, those with an amino-phenol or a masked amino-phenol structure are among the most cytotoxic compounds. Preliminary studies on 9-hydroxy- or 9-methoxyellipticines have shown that these molecules behave as "pro-alkylating" agents. In order to rationalize the "biooxidative alkylation" process for various ellipticine derivatives, we report in the present article (i) their electrochemical oxidation parameters, (ii) their biochemical oxidation, (iii) the ability of the oxidized forms to form adducts with nucleophiles, (iv) the biological activities, and (v) the electronic properties of oxidized forms. We present some possible correlations between the oxidizability, the electrophilicity of the oxidized derivatives, and the biological activities of the corresponding drugs.

Alkaloids↗
PubMedDate not supplied

Peptides quantitative structure-function relationships: an automated mutation strategy to design peptides and pseudopeptides from substitution matrices.

The process by which analogs in peptide chemistry are currently designed does not include any quantitative basis for amino acid substitutions from pharmacological leads. Here, we show that substitution matrices such as PAM 250 can provide quantitative constraints compatible with biological activity. This article describes its use in a strategy of rational amino acid substitution in peptides and proteins: we have computed a chemically derived matrix equivalent to the well-known PAM 250 matrix, reflecting the natural mutability rates of amino acids in protein evolutions but that can be extended to all the noncoded amino acids. Some of these noncoded amino acids are widely used to mimic secondary structure, to constrain backbone conformation, or to evade protease degradation. An automated sequence mutation (ASM) strategy has been defined to generate mutations within constraints. Application of such a substitution matrix to quantitative structure-function relationship studies will be of use in the design of proteins and peptides destined to become pharmaceutical drugs. In particular, issues such as which functionally conserved substitutions are able to satisfy conformational restrictions, oral bioavailability, or formulation demands can be quantitatively addressed.

Amino Acid Substitution↗