Aminolevulinic Acid Synthetase (ALA Synthetase)

The first step making porphyrins is synthesis of -aminolevulinic acid (ALA) catalyzed by the pyridoxal phosphate-containing enzyme, -aminolevulinic acid synthetase (ALA synthestase) (Figure 21.28). In plants, ALA is made in a process that begins with glutamate, which becomes linked to a tRNA (Figure 21.29). In plants, synthesis of ALA is regulated by light.

1. Porphyrin and Chlorophyll Metabolism

2. Photosynthetic Pigments