Aminolevulinic biosynthesis from glutamate

S.I. Beale (1990). Biosynthesis of the tetrapyrrole pigment precursor, (5-Aminolevulinic acid, from glutamate. Plant Physiol., 93, 1273-1279. 

The biosynthesis of 5-aminolevulinic acid (ALA, a chlorophyll precursor) was studied in greening barley leaves. Preliminary long-term experiments showed that radioactivity from glycine-2-C (or-carbon labeled) and from glutamate-2,S.-C " (methylene carbons labeled) appeared in ALA. The specific activity data of a more detailed study is shown in Figure 6-6. What conclusions can be drawn ... 

Fig. 2. Biosynthesis of 5-aminolevulinate in some photosynthetic bacteria, in cyanobacteria, higher plants and algae. The tRNA involved has also been called 6-aminolevulinic acid-RNA (6-ALA-RNA), but it appears to be identical to the tRNA used by chloroplasts for translation of chloro-plast mRNA. Chloroplast glutamic acid tRNA liga-ses (glutamyl-tRNA synthetases) have been purified to homogeneity from several sources. The final reaction is an intramolecular transamination, which, like conventional intermoleculartransaminations, requires pyridoxal phosphate.

---