Protein involved in the synthesis of chlorophylls. These photosynthetic pigments are magnesium-porphyrin complexes with a long hydrophobic terpenoid side chain (the alcohol phytol). Angiosperms have only a light-dependent pathway for chlorophyll biosynthesis, other oxygenic organisms seem to have both the light-dependent and the light-independent pathways. Non-oxygenic organisms, which make bacteriochlorophyll, only have a light-independent pathway.