The glycation of hemoglobin is catalyzed by buffer phosphate and arsenate. The catalytic constant （kB） for aqueous arsenate is two-fold larger than for aqueous phosphate. The catalytic constant （ks） of phosphate i...The glycation of hemoglobin is catalyzed by buffer phosphate and arsenate. The catalytic constant （kB） for aqueous arsenate is two-fold larger than for aqueous phosphate. The catalytic constant （ks） of phosphate in sorbitol mixtures increase from （1.67 ± 0.11） × 10-10 s-1·M-1 to （5.78 ± 0.39） × 10-10 s-1·M-1 and the catalytic constant is enhanced 3.5 times, relative to that in water; the catalytic constant （kB） of arsenate in sorbitol mixtures increase from （2.98±0.07）× 10-10 s-1·M-1 to （6.62 ± 0.53） × 10-10 s-1·M-1 and the catalytic constant is enhanced 2 times, relative to that in water. The spontaneous rate constants are independent of sorbitol concentration for phosphate and arsenate. The catalytic power of phosphate and arsenate in sorbitol are the same. Desolvation of strongly hydrated species such as HPO42 and HAsO42 should make a contribution to the energy cost of the formation of anion-hemoglobin complexes and can be a possible explanation for higher catalytic potential of HAsO42 in water. The same catalytic constant （ksB） for phosphate and arsenate in sorbitol indicates that the same catalyst base group on the hemoglobin molecule may be involved in the abstraction of proton in the Amadori rearrangement.展开更多
文摘The glycation of hemoglobin is catalyzed by buffer phosphate and arsenate. The catalytic constant （kB） for aqueous arsenate is two-fold larger than for aqueous phosphate. The catalytic constant （ks） of phosphate in sorbitol mixtures increase from （1.67 ± 0.11） × 10-10 s-1·M-1 to （5.78 ± 0.39） × 10-10 s-1·M-1 and the catalytic constant is enhanced 3.5 times, relative to that in water; the catalytic constant （kB） of arsenate in sorbitol mixtures increase from （2.98±0.07）× 10-10 s-1·M-1 to （6.62 ± 0.53） × 10-10 s-1·M-1 and the catalytic constant is enhanced 2 times, relative to that in water. The spontaneous rate constants are independent of sorbitol concentration for phosphate and arsenate. The catalytic power of phosphate and arsenate in sorbitol are the same. Desolvation of strongly hydrated species such as HPO42 and HAsO42 should make a contribution to the energy cost of the formation of anion-hemoglobin complexes and can be a possible explanation for higher catalytic potential of HAsO42 in water. The same catalytic constant （ksB） for phosphate and arsenate in sorbitol indicates that the same catalyst base group on the hemoglobin molecule may be involved in the abstraction of proton in the Amadori rearrangement.
