Mechanism of Site-Directed Protein Cross-Linking. Protein-Directed Selectivity in Reactions of Hemoglobin with Aryl Trimesates
摘要:
Site-directed cross-linking of hemoglobin has become an efficient way to produce a structurally defined altered protein with desirable functional properties. The reagent trimesoyl tris(3,5-dibromosalicylate) (1) introduces a bis amide cross-link derived from the epsilon-amino groups of the side chains of the two beta-Lys-82 residues in human hemoglobin. The basis of its specificity was investigated using a set of analogues of 1 (2-12). There are marked differences in the reaction patterns of these compounds with amino groups in hemoglobin compared to reactions with n-propylamine. The compounds that effectively modify the protein contain a carboxyl group ortho to the phenolic oxygen of the ester, while materials with meta or para carboxyl groups give little or no reaction. In contrast, the reactions with n-propylamine are slowest with the ortho carboxyl materials. Addition of the unreactive compound 5 to a solution containing hemoglobin reduces the ability of 1 to modify the protein, showing that the unreactive compound binds but does not react. On the basis of these observations and the known reaction patterns of salicylates, it is clear that: the environment in the protein controls the reaction, regardless of the inherent reactivity of the reagent. We propose that the carboxyl group positions the reagent critically within the protein. Only the ortho arrangement permits transfer of the acyl function to the nucleophile.
Barluenga, Jose; Jimenez-Aquino, Agustin; Aznar, Fernando, Journal of the American Chemical Society, 2009, vol. 131, p. 4031 - 4041
作者:Barluenga, Jose、Jimenez-Aquino, Agustin、Aznar, Fernando、Valdes, Carlos
DOI:——
日期:——
Novel nicotinoid structures for covalent modification of wood: an environmentally friendly way for its protection against insects
作者:Martin Söftje、Sophie Acker、Rudy Plarre、Jan C. Namyslo、Dieter E. Kaufmann
DOI:10.1039/d0ra02071k
日期:——
Timber is constantly exposed to environmental influences under outdoor conditions which limits its lifetime and usability. In order to counteract the damaging processes caused by insects, we have developed a novel and more environmentally friendly method to protect wood materials via covalent modification by organic insecticides. Starting with an important class of synthetic insecticides which are
Mechanism of Site-Directed Protein Cross-Linking. Protein-Directed Selectivity in Reactions of Hemoglobin with Aryl Trimesates
作者:Ronald Kluger、Vittorio De Stefano
DOI:10.1021/jo991514n
日期:2000.1.1
Site-directed cross-linking of hemoglobin has become an efficient way to produce a structurally defined altered protein with desirable functional properties. The reagent trimesoyl tris(3,5-dibromosalicylate) (1) introduces a bis amide cross-link derived from the epsilon-amino groups of the side chains of the two beta-Lys-82 residues in human hemoglobin. The basis of its specificity was investigated using a set of analogues of 1 (2-12). There are marked differences in the reaction patterns of these compounds with amino groups in hemoglobin compared to reactions with n-propylamine. The compounds that effectively modify the protein contain a carboxyl group ortho to the phenolic oxygen of the ester, while materials with meta or para carboxyl groups give little or no reaction. In contrast, the reactions with n-propylamine are slowest with the ortho carboxyl materials. Addition of the unreactive compound 5 to a solution containing hemoglobin reduces the ability of 1 to modify the protein, showing that the unreactive compound binds but does not react. On the basis of these observations and the known reaction patterns of salicylates, it is clear that: the environment in the protein controls the reaction, regardless of the inherent reactivity of the reagent. We propose that the carboxyl group positions the reagent critically within the protein. Only the ortho arrangement permits transfer of the acyl function to the nucleophile.