| Popis: |
The activation reaction of cross-linked agarose with 1,1′-carbonyldiimidazole (CDI) has been extended to other carbonylating reagents, and has confirmed that CDI allows the facile preparation of activated matrices suitable for affinity chromatographic supports. These studies showed that 1,1′-carbonyldi-1,2,4-triazole (CDT) gave a more reactive activated matrix, while 1,1′-carbonyldi-1,2,3-benzotriazole reacted only slowly and inefficiently. Phosgene, in addition to the disadvantage of toxicity, does not give a high level of activation. The introduction of imidazolyl carbamate groups onto cross-linked agarose by generating CDI in situ from phosgene and imidazole gave one-third of the level of activation of that obtained with pure CDI. All of the activated matrices had sufficient stability to aqueous conditions to allow unhurried isolation of the washed, activated product. All carbonylated matrices when subsequently coupled with monoalkylamines were found to be devoid of any additional charged groups due to the activation process. The studies have demonstrated that CDI is the most effective and convenient of the carbonylating reagents studied for the preparation of activated matrices to be used in affinity chromatographic experiments. However, the CDT-activated matrix is much more reactive than the CDI matrix and may be useful for the coupling of unstable protein ligands where short coupling times are essential. |
