Regulation of chloroplastic carbonic anhydrase : effect of magnesium.
It was previously reported that magnesium ion inhibited carbonic anhydrase (Bamberger and Avron 1975 Plant Physiol 56: 481-485). Studies with partially purified carbonic anhydrase from spinach (Spinacia oleracea L.) chloroplasts show that the effect was the result of the chloride counterion and not the magnesium ion. Enzyme activity was reduced 50% upon addition of 3 to 10 millimolar MgCl(2) or KCl while all additions of MgSO(4) between 0.3 and 10 millimolar were mildly stimulatory.
Porter
M A
MA
Department of Horticulture Science, University of Guelph, Guelph, Ontario N1G 2W1 Canada.
Grodzinski
B
B