Evidence was obtained by means of low temperature spectrofluorimetry and high pressure liquid chromatography for the exclusive chelation of Mg(2+) into protoporphyrin IX by a plastid preparation extracted from greening cucumber cotyledons. Under the experimental conditions which were optimized for Mg(2+) chelation, Zn(2+) chelation was not detected. However, Zn(2+) chelation was observed when ATP was omitted and ZnCl(2) was added to the incubation mixture. The observed Zn(2+) chelation was partially nonenzymic. The requirements for the enzyme, Mg chelatase, are discussed in terms of the regulatory function of this enzyme.
No takes yet. Share an insight, caveat, or question.
Fuesler et al. (1981) studied this question.