Inhibited by Ca2+, Mg2+?and especially Hg2+. SGR has very low activity with chlorophyllide?a?and none with chlorophyll?b. It acts on chlorophyll?a?both in its free form and in protein complex. SGRL, on the other hand, is more active with chlorophyllide?a?than with chlorophyll?a. The magnesium formed is scavenged by MCS (metal-chelating substance).
Cofactor
History
Reactions
(1) Chlorophyll a + 2 H(+) = pheophytin a + Mg(2+). (2) Chlorophylide a + 2 H(+) = pheophorbide a + Mg(2+).
