Carbon metabolism

Abstract

Photosynthetic eukaryotes synthesize organic compounds through photosynthesis. The compounds are then consumed for energy production or converted into other compounds through various metabolic pathways in organelles. Recently, studies on carbohydrate and lipid metabolism were performed on the red alga Cyanidioschyzon merolae. These studies were possible due to advancements in genomics and transformation techniques. The C. merolae genome encodes enzymes related to basic carbohydrate and lipid metabolism, and the subcellular distribution of metabolic pathways of C. merolae is basically identical to that of land plants. However, some metabolic enzymes, such as NAD-dependent malic enzyme, glyoxylate cycle enzymes, some mitochondrial translocators, and several fatty acid desaturases, are not found in C. merolae, indicating the metabolic pathways of C. merolae are simpler than those of green plants. In this chapter, we will summarize our current understanding of carbon metabolism and describe unique features of C. merolae metabolism by comparing metabolic enzymes among different species of sequenced red algae.