They also play important roles in biosynthetic pathways, including extracellular polysaccharide biosynthesis and cytochrome biogenesis. Androgen synthesis inhibitors are enzyme inhibitors that prevent the biosynthesis of androgens. These bacteria synthesize pantothenate from the amino acid aspartate and a metabolite in valine biosynthesis. Doxorubicin interacts with DNA by intercalation and inhibition of macromolecular biosynthesis. MCAT is also involved in bacterial polyketide biosynthesis. It plays a key role in chain elongation in fatty acid biosynthesis and polyketide biosynthesis. Experimentally, resistance usually arises as a result of mutations in the sterol biosynthesis pathway. Acetate in the cytosol is unavailable for lipid biosynthesis in the plastid. It includes food intake, absorption, assimilation, biosynthesis, catabolism and excretion. PHA synthases are the key enzymes of PHA biosynthesis. The resulting carbanions are key intermediates in many reactions in organic synthesis and biosynthesis. GPDH plays a major role in lipid biosynthesis. The pathway of estrogen biosynthesis in extragonadal tissues is different. The plant genes for ABA biosynthesis and sequence of the pathway have been elucidated. MAIT cells are activated by compounds derived from bacterial vitamin B2 (riboflavin) biosynthesis.