Ontology highlight
ABSTRACT:
SUBMITTER: Mikulski R
PROVIDER: S-EPMC3044917 | biostudies-literature | 2011 Feb
REPOSITORIES: biostudies-literature
Mikulski Rose R Avvaru Balendu Sankara BS Tu Chingkuang C Case Nicolette N McKenna Robert R Silverman David N DN
Archives of biochemistry and biophysics 20101209 2
The rate limiting step in catalysis of bicarbonate dehydration by human carbonic anhydrase II (HCA II) is an intramolecular proton transfer from His64 to the zinc-bound hydroxide. We have examined the role of Tyr7 using site-specific mutagenesis and measuring catalysis by the ¹⁸O exchange method using membrane inlet mass spectrometry. The side chain of Tyr7 in HCA II extends into the active-site cavity about 7 Å from the catalytic zinc atom. Replacement of Tyr7 with eight other amino acids had n ...[more]