کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1178272 962678 2010 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Proton transfer in catalysis and the role of proton shuttles in carbonic anhydrase
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Proton transfer in catalysis and the role of proton shuttles in carbonic anhydrase
چکیده انگلیسی

The undisputed role of His64 in proton transfer during catalysis by carbonic anhydrases in the α class has raised questions concerning the details of its mechanism. The highly conserved residues Tyr7, Asn62, and Asn67 in the active-site cavity function to fine tune the properties of proton transfer by human carbonic anhydrase II (HCA II). For example, hydrophobic residues at these positions favor an inward orientation of His64 and a low pKa for its imidazole side chain. It appears that the predominant manner in which this fine tuning is achieved in rate constants for proton transfer is through the difference in pKa between His64 and the zinc-bound solvent molecule. Other properties of the active-site cavity, such as inward and outward conformers of His64, appear associated with the change in ΔpKa; however, there is no strong evidence to date that the inward and outward orientations of His64 are in themselves requirements for facile proton transfer in carbonic anhydrase.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics - Volume 1804, Issue 2, February 2010, Pages 422–426
نویسندگان
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