| Literature DB >> 4216018 |
Abstract
Zinc ion-induced pyrrole hydrogen ionization from a histidyl residue has recently been suggested as the source of the activity-related deprotonation in carbonic anhydrase (EC 4.2.1.1; carbonate hydro-lyase) occurring at pH 7-8. The results offered to support the hypothesis are shown to be deficient. Examination of the literature reveals no precedent for such a pronounced acidification from pK(a) [unk] 14.2 in imidazole compounds by zinc ion. It is suggested that Zn(II)-induced pyrrole ionizations in imidazoles occur with pK(a) about 13.Entities:
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Year: 1974 PMID： 4216018 PMCID： PMC433879 DOI： 10.1073/pnas.71.11.4346
Source DB: PubMed Journal: Proc Natl Acad Sci U S A ISSN： 0027-8424 Impact factor: 11.205