Role of Aldolase in Photosynthesis. II Demonstration of Aldolase Types in Photosynthetic Organisms

Spinach leaves and photoautotrophically grown Euglena and Chlorella possess fructose 1,6-diphosphate aldolases inhibited by p-chloromercuribenzoate but insensitive to K+ or ethylenediamine tetraacetate (Type I). Dark grown Euglena and Chlorella have aldolases inhibited by p-chloromercuribenzoate and ethylenediamine tetraacetate but stimulated by K+ (Type II). The red alga, Chondrus, and the golden-brown alga, Ochromonas, appear to possess both types. Bean, pea, and spinach seeds and the leaves and cotyledons of etiolated bean seedlings contain a p-chloromercuribenzoate insensitive, apparently non-sulfhydryl variant of Type I. Sensitivity of leaf aldolase to p-chloromercuribenzoate occurs in etiolated bean seedlings only after an extended period of illumination. Type II aldolase activity in cell-free extracts of 4 blue-green algae has been demonstrated.