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Carbon dioxide hydration activity and metal—substrate distances of manganese (II) human carbonic anhydrase B determined by 13 C magnetization—transfer NMR
Author(s) -
Led Jens J.,
Neesgaard Ebbe,
Johansen Jack T.
Publication year - 1982
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(82)81014-4
Subject(s) - manganese , chemistry , carbonic anhydrase , substrate (aquarium) , metal , magnetization , paramagnetism , crystallography , enzyme , relaxation (psychology) , active site , inorganic chemistry , stereochemistry , organic chemistry , psychology , social psychology , oceanography , physics , quantum mechanics , magnetic field , geology
A CO 2 hydration activity for Mn(II) human carbonic anhydrase B (MnHCAB) of 7% of the activity of the native Zn 2+ enzyme has been determined using a 13 C magnetization—transfer NMR approach, that involves two complementary experiments. As this approach also allows a determination of the individual relaxation rates of the enzyme‐bound CO 2 and HCO − 3 , an evaluation could be made of the distances between these substrates and the paramagnetic Mn 2+ in the active site. Thus HCO − 3 is found to bind directly to Mn 2+ , whereas CO 2 is attached relatively weakly to the enzyme without a direct bond to the metal ion.