Metabolism of δ-Aminolevulinic Acid in Red and Blue-Green Algae

Abstract

5-Aminolevulinic acid was incorporated in vivo into C-phycocyanin and B-phycoerythrin in two species of the Rhodophyta (Cyanidium caldarium, Porphyridium cruentum) and three species of the Cyanophyta (Anacystis nidulans, Plectonema boryanum, Phormidium luridum). Amino acid analysis of phycocyanin-'4C from C. caldarium cells which had been incubated with 5-aminolevulinate-4-'4C showed that 84% of the radioactivity incorporated was present in the phycocyanobilin chromophore and less than 16% of the radioactivity cochromatographed with amino acids. These results indicate that 8-aminolevulinate is utilized predominantly via the porphyrin pathway in C. caldarium. Conversely, analysis of phycocyanin-"C prepared from cells of A. nidulans, P. boryanum, and P. luridum which had been incubated with radiolabeled 5-aminolevulinate demonstrated that 85 %, 81 %, and 93 %, respectively, of the radioactivity incorporated cochromatographed with amino acids. The ratio of incorporated radioactivity in amino acids and phycoerythrobilin was 40:60 in P. cruentum phycoerythrin obtained from cells which had been incubated with 3-aminolevulinate-4-"C. Succinate-2-3-'4C appeared to be as good a carbon source of amino acids as did C4 and C5 of 6-aminolevulinate. These data demonstrate a major alternate route (other than the porphyrin pathway) of 8-aminolevulinate metabolism in red and blue-green algae. The factors responsible for the extent to which 6-aminolevulinate is utilized for synthesis of porphyrins and their derivatives and routes of 5-aminolevulinate catabolism in the organisms employed are discussed.

Biosynthesis of delta-aminolevulinic acid by blue-green algae (cyanobacteria)

“…ALA is the precursor of heme in animals (17) and bacteria (10) and of chlorophyll in bacteria (5) and plants (7). Troxler and Brown (19) have shown that radioactively labeled ALA is incorporated into the chromophores (phycocyanobilin and phycoerythrobilin) of phycocyanin and phycoerythrin by red algae. Levulinic acid (LA), which is structurally similar to ALA except for the absence of the amino group, has been shown by Nandi and Shemin (15) to be a competitive inhibitor of ALA dehydratase.…”

Catabolism of 5-Aminolevulinic Acid to CO2 by Etiolated Barley Leaves

“…However, there is a growing body of evidence which indicates that ALA may be metabolized via nonporphyrin pathway(s) in a number of organisms (7,13,15). For example, etiolated barley leaves evolve '4C02 when fed [4-14C]ALA or [5-14C]ALA in the dark (7).…”

Biosynthesis of δ-Aminolevulinic Acid from Glutamate in Agmenellum quadruplicatum

“…ALA2 is the precursor of heme in animals (16) and bacteria (9); of Chl in bacteria (6) and plants (8); and of the phycobilins in red algae (19). In many organisms ALA is formed by the condensation of glycine and succinyl-CoA, catalyzed by ALA synthetase, a pyridoxal-requiring enzyme.…”