Nature of the aldolase acitivity in a unicellular red alga.

Abstract

THE occurrence of fructose-1,6-diphosphate (FDP) aldolase in red algae (Rhodophyta) has been the subject of some controversy. Whereas Jacobi1 reported the absence of aldolase in four species of multicellular red algae, Fewson et al.2 were able to demonstrate activity of this enzyme in extracts of a multicellular species (Chondrus crispus) and a unicellular species (Porphyridium cruentum). The recent discovery of aldolase in blue–green algae (Cyanophyta)3,4 after earlier failures2,5 to detect it in this algal group indicates the need for similar re-examination and characterization of aldolase in the red algae. During comparative investigations on aldolase activity in marine phytoplankton species belonging to several classes of algae, we had occasion to re-examine the unicellular red alga Porphyridium cruentum Nageli and were able to confirm activity. Furthermore, a developing interest in the biochemical evolution of aldolase6 prompted us to investigate certain characteristics of this enzyme activity, and we have obtained interesting results which may be of value to algal phylogeny.